Literature review · 16 October 2026

NH₃-TPD on Ni–Mo / alumina catalysts

Primary experimental evidence relevant to NiMo/γ-Al₂O₃, Ni/γ-Al₂O₃, and Mo/γ-Al₂O₃, organized by the sample state during acidity characterization. Emphasis: support controls, quantitative uptake, and reproducible methods for interpreting a NiMo/Al₂O₃ anisole-HDO manuscript.

13 primary journal studies5 state categoriesDOI links in every entryUnreported details explicitly flagged
Main conclusion

The strongest direct comparators are Hossain et al. (2018) for paired Mo/γ-Al₂O₃ and Ni/γ-Al₂O₃ with numerical NH₃ uptake; the 2025 PET-pyrolysis study for an Al₂O₃ blank plus Mo/Al₂O₃ and NiMo/Al₂O₃ composition series; the 2020 fluoride-modified NiMo study for a clearly identified sulfided-state series and detailed TPD protocol; and the 2024 vanillin-HDO study for support/catalyst controls and an HDO-relevant NH₃-TPD comparison (but it uses δ-Al₂O₃, not γ-Al₂O₃). These are complementary rather than directly rankable: adsorbate uptake, pretreatment, support phase, and normalization differ.

Interpretation boundary

NH₃-TPD total uptake is not, by itself, a Lewis/Brønsted measurement or a direct count of HDO-active sites. Do not compare peak areas or “weak/medium/strong” bins across papers unless pretreatment, NH₃ dose/purge, ramp, detector calibration, support phase, and mass normalization match. “Not reported” means the primary text or accessible record did not state the detail; it has not been inferred.

At-a-glance evidence

Evidence needBest located source(s)What is actually reportedBoundary
Bare alumina + monometallic controlsLiu et al., 2025; vanillin-HDO, 2024PET paper compares Al₂O₃, Mo/Al₂O₃ and Ni–Mo/Al₂O₃ series; vanillin paper measures δ-Al₂O₃ and NiMo/δ-Al₂O₃, with Ce/La-doped controls.PET TPD method/state and absolute uptake are not reported in accessible text. Vanillin paper uses δ-, not γ-alumina; its quoted volumetric uptake is chemisorption, not integrated TPD uptake.
Quantified Ni-only vs Mo-onlyHossain et al., 2018Fresh 10 wt% Mo-, Ni-, and MgO-loaded γ-Al₂O₃ catalysts; total NH₃ desorbed: 33.5, 25.0, and 24.3 mL STP g⁻¹, respectively.No bare γ-Al₂O₃ TPD control reported in the accessible article; uptake is volume-based, not directly interchangeable with mmol g⁻¹ unless the standard conditions are confirmed.
Detailed sulfided-state methodHan et al., 2020Paper labels NH₃-TPD profiles as sulfided Ni–Mo/Al₂O₃; supplies sample mass, particle size, dose, purge gas, ramp and detectors.Absolute NH₃ uptake values are not reported in the accessible results; gas used in the 500 °C pretreatment is not reported.
Reduced-state HDO comparatorKumar et al., 2015; vanillin-HDO, 2024Both describe H₂ reduction before NH₃ acidity analysis; the 2015 SI calibrates the TCD with known NH₃ pulses.2015 paper’s numerical uptake is not transcribed here. 2024’s numerical total-acidity values are from chemisorption; TPD is used for strength distribution.
Phosphides / carbidesNi₂P/MoP, 2015; Mo₂C anisole HDO, 2014Supported Ni₂P and MoP have NH₃-TPD reported; the anisole Mo₂C paper is a reaction precedent.No verified NH₃-TPD study of a NiMo/γ-Al₂O₃ carbide was located. The Mo₂C anisole paper is not cited here as acidity evidence.

Fresh / oxide-precursor / state not separately reported

Entries remain in this group only when the authors report fresh or non-sulfided catalysts, or when the exact NH₃-TPD state is explicitly unavailable. A preparation calcination is not assumed to prove that the specimen remained an oxide during TPD.

Primary studies: oxides, fresh materials, and state-unspecified measurements

1. Hossain et al. (2018) — Continuous Hydrothermal Decarboxylation of Fatty Acids and Their Derivatives into Liquid Hydrocarbons Using Mo/Al₂O₃ Catalyst Ni + Mo controlsquantitative uptake

DOI: 10.1021/acsomega.8b00562 · Publisher article

Composition
10 wt% Mo/γ-Al₂O₃, 10 wt% Ni/γ-Al₂O₃, and 10 wt% MgO/γ-Al₂O₃. A bare γ-Al₂O₃ NH₃-TPD trace is not reported in the accessible paper.
TPD state
Fresh catalysts, as explicitly described; no reduction/sulfidation before NH₃-TPD is reported in the accessible method.
Acidity / methods
Total desorbed NH₃: Mo/Al₂O₃ 33.5, Ni/Al₂O₃ 25.0, MgO/Al₂O₃ 24.3 mL STP g⁻¹. The profiles are assigned mainly to Lewis-acid-associated desorption (about 100–350 °C), with a higher-temperature feature assigned by the authors to Brønsted acidity. Exact pretreatment/dose/ramp details: not accessible in the extracted article text.
Relevance
Direct monometallic Mo and Ni benchmarks on γ-alumina with numerical uptake. Reaction is fatty-acid decarboxylation in subcritical water, not anisole HDO; do not transfer its acidity ranking as an HDO selectivity prediction.

2. “Increased Light Olefin Production by Sequential Dehydrogenation and Cracking Reactions” (2022) Mo + NiMoquantitative acidity

DOI: 10.3390/catal12111457 · Open article

Composition
Mo/Al₂O₃ and Ni–Mo/Al₂O₃; exact metal loadings and alumina phase: not reported in the accessible excerpt. ZSM-5-based cracking catalysts are also characterized.
TPD state
Sample pretreatment and state during NH₃-TPD: not reported in the accessible method.
Acidity / methods
Reported total acidity is 86.5 μmol g⁻¹ for Ni–Mo/Al₂O₃, greater than Mo/Al₂O₃. The Mo/Al₂O₃ and Ni–Mo/Al₂O₃ desorption peaks are centered near 270 °C and described as weak-to-medium acidity. Absolute total NH₃ uptake for Mo/Al₂O₃ and the detailed TPD protocol: not reported in the accessible text.
Relevance
A paired Mo/NiMo alumina comparison and useful numeric anchor, but it concerns dehydrogenation/cracking of n-octane rather than oxygenate HDO; the alumina phase and preparation state must be checked before using it as a γ-Al₂O₃ precedent.

3. Liu et al. (2025) — Investigation on the Pyrolysis of Waste Poly(ethylene terephthalate) over NiMo Bimetallic Catalysts bare Al₂O₃ controlNi series

DOI: 10.1360/TB-2024-0921 · Publisher/DOI record

Composition
Al₂O₃, Mo/Al₂O₃, and NiMo/Al₂O₃ series labeled 1-, 2-, 3-, 4-, 5-, and 10NiMo; exact Mo loading and loading basis are not reported in the accessible text. The support phase is not reported.
TPD state
Not reported. The caption identifies H₂-TPR of “unreduced” catalysts, but that does not establish the NH₃-TPD pretreatment/state.
Acidity / methods
NH₃-TPD traces include Al₂O₃, Mo/Al₂O₃, and NiMo/Al₂O₃. Al₂O₃ has one desorption peak; Mo addition intensifies the weak-acid region; increasing Ni content enriches acid features, with medium/strong features more evident above 4 wt% Ni. Absolute NH₃ uptake and TPD protocol: not reported in accessible text.
Relevance
Best located exact-support-control design for a NiMo series. PET pyrolysis under H₂ is not a phenolic HDO test, and the unknown TPD pretreatment prevents state-to-state comparison.

4. Su et al. (2023) — Effect of Different Al₂O₃ Supports on the Synthesis of Tetralin by Selective Catalytic Hydrogenation of Naphthalene

DOI: 10.21577/0103-5053.20230011 · Open article

Composition
4% NiO–20% MoO₃/Al₂O₃ on commercial, co-precipitated, and sol–gel alumina supports; whether the percentages are oxide or elemental loading is stated in the paper’s formulation notation, not normalized here.
TPD state
Not reported for the NH₃-TPD step.
Acidity / methods
TP-5080 instrument with TCD. Reported bins: weak <200 °C, medium 200–400 °C, strong >400 °C. Ni–Mo/alumina is mainly medium/weak acidic; total acidity is highest for the sol–gel support and lowest for the co-precipitated support. Numerical uptake and dose/ramp details: not reported in accessible text. Bare-support NH₃-TPD: not reported.
Relevance
Shows preparation-route/support effects can exceed a simple NiMo-vs-Mo comparison; naphthalene hydrogenation is adjacent evidence, not HDO.

5. Huang et al. (2022) — Effect of Gallium as an Additive over Ni–Mo/γ-Al₂O₃ Catalysts on 4,6-DMDBT Hydrodesulfurization detailed method

DOI: 10.3389/fchem.2022.865375 · Open article

Composition
Ni–Mo/γ-Al₂O₃ with 2–6 wt% Ga₂O₃; base Ni and Mo loadings and a bare γ-Al₂O₃ TPD control: not reported in accessible text.
TPD state
Samples were pretreated in Ar/air (3:1) at 773 K for 60 min before NH₃ adsorption. This is an oxidatively pretreated sample, not a sulfided-state TPD.
Acidity / methods
NH₃ adsorption at 373 K for 40 min; Ar purge for 90 min; TPD at 10 °C min⁻¹ for 65 min with TCD. Peaks for Ga-modified samples lie mainly at 150–300 °C; Ga shifts desorption lower and increases weaker acidity while slightly decreasing strong Brønsted acidity. Peak areas are tabulated by the authors; no absolute calibrated uptake was found in the accessible extract.
Relevance
Explicit support phase and good protocol disclosure. HDS/oxidative pretreatment means its acid-strength distribution is not a measurement of an in-situ sulfided HDO catalyst.

6. Ultradeep Hydrodesulfurization of Feedstock Containing Cracked Gasoil through NiMo/γ-Al₂O₃ Catalyst Pore Size Optimization (2018)

DOI: 10.1021/acs.energyfuels.7b03461 · Publisher article

Composition
NiMo/γ-Al₂O₃ catalysts prepared on γ-alumina supports with varied pore sizes; exact Ni/Mo loading not reported in accessible abstract. Bare support NH₃-TPD is discussed.
TPD state
Not reported in accessible abstract.
Acidity / methods
Abstract reports about half of the total NH₃ (1.76 mmol NH₃ g⁻¹) as associated with γ-Al₂O₃ support acidity. The exact denominator/basis is ambiguous in the accessible abstract; verify the full paper before quoting as the uptake of bare support. Detailed TPD method not accessible.
Relevance
Potentially useful support-acidity control and quantitative lead; the unit/basis caveat is material, so it is not treated as a validated bare-support value here.

7. Hydrotreating of Heavy Gas Oil on Mesoporous Mixed Metal Oxides Supported NiMo Catalysts (2014)

DOI: 10.1021/ie500840d · Publisher record

Composition
NiMo on TiO₂–Al₂O₃, ZrO₂–Al₂O₃, SnO₂–Al₂O₃ and a NiMo/γ-Al₂O₃ comparative catalyst; exact loadings not reported in accessible abstract.
TPD state
Not reported in accessible abstract.
Acidity / methods
NH₃-TPD acidity-strength order: NiMo/SnO₂–Al₂O₃ > NiMo/ZrO₂–Al₂O₃ > NiMo/TiO₂–Al₂O₃. Absolute NH₃ uptake and TPD protocol not accessible in abstract.
Relevance
Demonstrates support composition can strongly change apparent acidity; petroleum hydrotreating, not HDO, and the mixed-oxide series should not be conflated with bare γ-Al₂O₃.

8. “Contrast Activities of Four Alumina and Alumina–Silica-Supported Nickel–Molybdenum Sulfide Catalysts for Deep Desulfurization of Gas Oils” (2005)

DOI: 10.1016/j.apcata.2004.10.048 · Publisher record

Composition
Four vendor-supplied NiMo sulfide catalysts on alumina and alumina–silica; exact loadings/formulations are not accessible in the abstract.
TPD state
Sulfide catalyst family is explicit in the title; exact state/handling at the NH₃-TPD step is not reported in the accessible abstract.
Acidity / methods
NH₃-TPD was used alongside BET and Raman. Absolute uptake, peak assignments, and TPD protocol: not accessible in the abstract.
Relevance
Relevant historical sulfided-NiMo comparator, but its accessible record is insufficient for a quantitative or detailed-method comparison.

Reduced catalysts

Hydrogen-reduced metal / oxide-derived HDO catalysts

9. Kumar et al. (2015) — Solvent-Free Depolymerization of Kraft Lignin to Alkyl-Phenolics Using Supported NiMo and CoMo Catalysts HDO-adjacentcalibrated TPD

DOI: 10.1039/C5GC01641J · Publisher article · Supporting information

Composition
Supported NiMo and CoMo catalysts, including NiMo/Al₂O₃; exact Ni/Mo loading is not reported in the accessible SI excerpt.
TPD state
Reduced in flowing H₂ at atmospheric pressure from room temperature to 500 °C at 10 °C min⁻¹ before TPD.
Acidity / methods
Approximately 50 mg sample; H₂ 60 STP mL min⁻¹; online TCD calibrated using known NH₃ pulses. The SI states that NH₃-TPD quantified acidic sites. Numerical uptake and detailed NH₃ adsorption/purge/ramp conditions: not present in the accessible SI excerpt.
Relevance
Most useful lignin-derived oxygenate precedent in this set for a reduced, nonsulfided NiMo catalyst. Its lignin depolymerization feed is chemically broader than anisole, so cite it as adjacent rather than direct anisole precedent.

10. Kristensen et al. (2024) — Promoting Effect of Ce and La on Ni–Mo/δ-Al₂O₃ Catalysts in the Hydrodeoxygenation of Vanillin HDO closestbare supportdetailed protocol

DOI: 10.1021/acs.energyfuels.4c00898 · Open full text

Composition
3.5 wt% Ni and 8.0 wt% Mo on δ-Al₂O₃; Ce- and La-doped support/catalyst comparisons; bare reference δ-Al₂O₃ measured. Not γ-Al₂O₃.
TPD state
Catalysts were reduced at 550 °C for 30 min in 10% H₂/Ar before acidity analysis; supports were not reduced. The paper also studies H₂S-assisted activation/reaction, but that is not the reported TPD state.
Acidity / methods
About 0.27 g; 3Flex; NH₃ dose 15 min at 50 °C; He 10 mL min⁻¹; TPD 50–700 °C at 10 °C min⁻¹. Complementary static NH₃ chemisorption values: reference δ-Al₂O₃/support catalyst 1.11/4.55 cm³ g⁻¹; Ce/La-doped support/catalyst 0.62/2.82 cm³ g⁻¹. These are chemisorption values, not integrated TPD uptake. TPD shows a roughly 50 °C lower strong-site desorption temperature and fewer strong sites after Ce/La modification.
Relevance
Direct phenolic HDO and the best state-aware methods comparator for anisole-HDO discussion. The different alumina phase and promoters limit direct transfer to γ-Al₂O₃.

Sulfided catalysts

NH₃-TPD explicitly associated with sulfided NiMo/alumina

11. Han et al. (2020) — Effect of Modified Carrier Fluoride on the Performance of Ni–Mo/Al₂O₃ Catalyst for Thioetherification state identifieddetailed method

DOI: 10.1007/s12182-020-00439-9 · Publisher article

Composition
Ni–Mo/Al₂O₃ series modified with fluoride; exact Ni/Mo loadings and alumina phase are not reported in the accessible extract. F-1 is identified as the 0.2% F optimum for the reaction.
TPD state
Authors explicitly call Figure 2 profiles “sulfided state.” NH₃-TPD procedure then includes a 500 °C/30 min pretreatment; gas for that pretreatment is not reported, so the surface state after this step is not independently established.
Acidity / methods
0.2 g, 20–40 mesh; Ar 40 mL min⁻¹; NH₃ 20 mL min⁻¹; adsorption 100 °C for 30 min; ramp 10 °C min⁻¹ to 800 °C; TCD and MS detection. Increasing F increases strong-acid and total-acid signal; after 60 h on stream, strong acidity disappears and weak acidity/total acidity decrease. Absolute calibrated uptake: not reported in accessible results.
Relevance
Strongest methods reference for state-labeled sulfided NiMo/Al₂O₃ in this set. Thioetherification is not anisole HDO; use for acidity/pretreatment method, not selectivity prediction.

Phosphides and phosphorus-containing catalysts

Keep phosphide phase identity separate from P-modified Ni or mixed phosphidic–sulfidic materials

12. Peroni et al. (2015) — Bulk and γ-Al₂O₃-Supported Ni₂P and MoP for Hydrodeoxygenation of Palmitic Acid true phosphides

DOI: 10.1016/j.apcatb.2015.06.042 · Publisher record

Composition
Bulk and γ-Al₂O₃-supported Ni₂P and MoP prepared from metal salts/phosphate; Ni/P and Mo/P precursor molar ratios were 0.5 and 1, respectively. Catalyst loadings and individual NH₃-TPD uptake values: not accessible in the retrieved record.
TPD state
Supported phosphides produced by temperature-programmed reduction; exact NH₃-TPD pretreatment and passivation history: not accessible.
Acidity / methods
NH₃-TPD was used with XRD, TEM, BET and CO adsorption. Al₂O₃ promotes acid-catalyzed pathways and affects phosphide functionality; absolute uptake and peak distribution: not accessible in the retrieved record.
Relevance
True Ni₂P/MoP HDO comparator, but not a NiMo sulfide or NiMo oxide. Keep its phase family separate in any acidity table.

12. Yu et al. (2019) — Hydrodeoxygenation of Phenolic Compounds to Cycloalkanes over Supported Nickel Phosphides important phase caveat

DOI: 10.1016/j.cattod.2018.05.012 · Accessible manuscript copy

Composition
20 wt% Ni with Ni/P precursor molar ratios 3, 2 and 1; Ni-P/Al₂O₃ included. The authors report that Al₂O₃-supported samples formed Ni metal rather than nickel phosphide.
TPD state
Passivated sample was re-reduced in H₂ for 1 h at 500 °C before NH₃ adsorption.
Acidity / methods
0.2 g sample; NH₃ adsorption at 40 °C for 30 min; He ramp 10 °C min⁻¹ to 500 °C. The paper reports weak- and strong-acid desorption peaks; numerical table values are not accessible in the extracted text.
Relevance
Useful warning against calling every Ni–P/Al₂O₃ sample a phosphide. For a state-based comparison, this paper belongs under reduced Ni/P-modified material on alumina, not as a confirmed Ni₂P/Al₂O₃ result.

13. Puello-Polo et al. (2022) — Al₂O₃–MgO-Supported Ni, Mo, and NiMo Mixed Phosphidic–Sulphidic Phase for Green Diesel

DOI: 10.3389/fchem.2022.880051 · Open full text

Composition
MoP–S, NiP–S, and NiMoP–S on γ-Al₂O₃–MgO, with Al/Mg about 37 and Mo:Ni:P about 1; sulfur up to 4.5 wt% is reported.
TPD state
Mixed phosphidic–sulfidic materials. The study reports Py-TPD, not NH₃-TPD.
Acidity / methods
No NH₃-TPD result or NH₃ uptake is reported; it must not be counted as an NH₃-TPD study. Py-TPD findings indicate more Brønsted/Lewis sites for NiMoP–S/γ-Al₂O₃–MgO, with Lewis sites decreasing as temperature increases.
Relevance
Listed only to prevent a common method/phase conflation; adjacent fatty-acid HDO evidence, not NH₃-TPD evidence and not pure γ-Al₂O₃.

Carbides

No verified primary study of NH₃-TPD on a NiMo/γ-Al₂O₃ carbide was located in this screened set. Do not fill this category by borrowing oxide or sulfide acidity values.

A direct anisole-HDO molybdenum-carbide paper exists—Lee et al., “Selective vapor-phase hydrodeoxygenation of anisole to benzene on molybdenum carbide catalysts”—but the accessible record did not establish that it reports NH₃-TPD. It is therefore a reaction-pathway comparator only, not acidity evidence. A NiMoC/β-zeolite NH₃-TPD study is also adjacent but uses zeolite rather than alumina.

For manuscript language: state that carbide-phase NH₃-TPD data were not identified in this search, rather than asserting none exist.

How to use this evidence in an anisole-HDO manuscript

Closest primary comparisons

Use Hossain et al. for Ni-only versus Mo-only γ-Al₂O₃ uptake; use the 2025 PET paper for a bare Al₂O₃ / Mo / NiMo support-controlled series; use the 2024 vanillin paper for a reduced NiMo HDO acidity comparison, explicitly noting δ-Al₂O₃ and chemisorption-versus-TPD distinctions.

State discipline

Report the exact specimen entering NH₃-TPD: calcined oxide, H₂-reduced, sulfided, phosphide, carbide, passivated/re-reduced, or spent. If the source does not state it, write “not reported”; do not infer it from the reaction catalyst or H₂-TPR panel.

Controls to prioritize

Measure bare γ-Al₂O₃; Ni/γ-Al₂O₃; Mo/γ-Al₂O₃; NiMo/γ-Al₂O₃ at matched total loading and matched calcination/activation history. For sulfided catalysts, include both oxide precursor and sulfided specimen only if the NH₃-TPD pretreatment preserves/defines the sulfide state.

Reportability

State instrument/detector and calibration; sample mass/particle size; pretreatment gas, temperature, duration; NH₃ concentration, temperature, dose time; purge conditions; ramp/end temperature; and uptake basis (µmol NH₃ g⁻¹ catalyst, support, or accessible surface). Include raw profiles and integrated calibrated totals.

Do not overstate the structure–selectivity link

For anisole, NH₃-TPD can support an acidity comparison but cannot alone identify the pathway to benzene, phenol, cresols, cyclohexanol, or cyclohexane. Pair acidity with matched catalyst state, product carbon balance/selectivity, and complementary probes (e.g., pyridine-IR or selective poisoning) before assigning a role to acid sites.

Screening and limitations