25 distinct research papers on alumina, silica–alumina and zeolites, including direct poisoning studies and explicitly marked related evidence.
Proposed, not a published protocol: compare the same untreated alumina with a reagent-solvent blank and several measured alkali loadings; keep drying, calcination and any metal deposition sequence identical where feasible. Include a KOH series and, if practical, a potassium-salt counterion control. The choice of nominal loading must be adapted to measured acid-site density and support stability.
Measure K uptake/leaching and surface area, and use matched-state pyridine IR to distinguish accessible Lewis and Brønsted acidity; temperature-resolved NH₃-TPD can complement it but cannot by itself distinguish those site types. CO₂ adsorption/TPD can assess basicity separately. Include a support-only and a complete-catalyst series to identify metal–promoter confounding [2,4,7,9]. Compare product yield, selectivity, stability and mass balance—not conversion alone.
Key reporting details: precursor identity and counterion; loading basis and actual K content; impregnation method and solution pH; calcination/reduction atmosphere and temperature; support phase; acidity measurement pretreatment; and whether any apparent change is normalized per gram or area. Strong alkaline solutions may also alter oxide structure, making matched controls essential.
Ordered by relevance, not by citation count. DOI links lead to publisher records; full text may be restricted. Descriptions are bounded by the evidence levels shown.
Alkali poisoning of γ-alumina was studied using acidity and isopropanol dehydration. The reported poisoning depends on the alkali cation and affects the acid-strength distribution. DOI: 10.1002/jctb.280530212
Evidence accessed: Abstract. Verify full experimental details before implementation.FTIR and temperature-programmed desorption characterize potassium-doped alumina. A priority source for comparing surface acidity and basicity; accessible information did not establish a quantitative neutralization fraction. DOI: 10.1016/j.apcata.2011.04.016
Evidence accessed: Abstract. Verify full experimental details before implementation.Alkali promotion of chromia–alumina was studied by IR probes; the authors report elimination of Lewis acidity and increasing basic-site strength along the alkali series. Chromia complicates attribution to bare alumina. DOI: 10.1246/cl.1980.327
Evidence accessed: Abstract. Verify full experimental details before implementation.Study of potassium addition, acidity and reducibility of chromia/alumina; changes in the metal oxide and support cannot automatically be separated. DOI: 10.1016/S0926-860X(03)00308-9
Evidence accessed: Abstract. Verify full experimental details before implementation.Studies the interfacial chemistry of preparing potassium-modified alumina from potassium carbonate. Useful for impregnation and activation, but not by itself proof of quantitative acid-site neutralization. DOI: 10.1039/FT9938902527
Evidence accessed: Abstract. Verify full experimental details before implementation.Examines synthesis and characterization of potassium-modified alumina superbases using carbonate/bicarbonate precursors. Increased basicity is not equivalent to a measured loss of a specific acid-site population. DOI: 10.1039/B100084P
Evidence accessed: Abstract. Verify full experimental details before implementation.Pyridine IR examines acid sites after NaOH poisoning. Both Lewis and Brønsted site populations are affected; the study differentiates site type and apparent strength. DOI: 10.1246/bcsj.51.1581
Evidence accessed: Publisher abstract. Verify full experimental details before implementation.Potassium modification of silica-supported vanadium oxide and propene oxidation: a metal-oxide-containing catalyst, not bare support neutralization. DOI: 10.1016/j.jcat.2016.12.001
Evidence accessed: Abstract. Verify full experimental details before implementation.Increasing K content reduces acid sites and changes n-hexane dehydrogenation selectivity; it also changes the Pt function, preventing attribution of performance solely to acidity. DOI: 10.1039/D4NJ01967A
Evidence accessed: Publisher abstract. Verify full experimental details before implementation.Studies the effect of sodium impurities in γ-alumina on ethanol dehydration, an acid-sensitive probe reaction. Sodium is an impurity rather than necessarily an added hydroxide. DOI: 10.1016/0021-9517(67)90318-1
Evidence accessed: Abstract. Verify full experimental details before implementation.Compares sodium impurity and amorphization effects on γ-alumina Lewis acidity, using spectroscopic and reaction evidence. Structure and sodium must be disentangled. DOI: 10.1016/0926-860X(93)80046-S
Evidence accessed: Abstract. Verify full experimental details before implementation.For one γ-alumina, the abstract reports that 400 ppm Na reduced isopropanol dehydration reactivity by 75%. This is a rate/activity change, not a direct 75% site count. DOI: 10.1016/0926-860X(95)00161-1
Evidence accessed: Abstract. Verify full experimental details before implementation.IR spectroscopy companion to the preceding study: examines surface hydroxyl groups and sodium/structure effects on acidity. The accessible record does not establish a numerical site loss. DOI: 10.1016/0926-860X(95)00162-X
Evidence accessed: Abstract / metadata. Verify full experimental details before implementation.Examines how sodium oxide affects alumina morphology and basicity. Useful for distinguishing structural and basicity changes from acid-site measurements. DOI: 10.1016/0926-860X(95)00149-2
Evidence accessed: Abstract / metadata. Verify full experimental details before implementation.Examines Ni–Mo catalysts on sodium- and magnesium-modified alumina and their acid–base and hydrofining behavior. Metal phase effects are a major confounder. DOI: 10.1016/S0926-860X(97)00354-2
Evidence accessed: Abstract. Verify full experimental details before implementation.Studies catalytic activity and selectivity of NaOH-doped γ-aluminas using 3-pentanol dehydration and dehydrogenation. Detailed doses and site measurements require the full paper. DOI: 10.1039/F19726800773
Evidence accessed: Metadata / abstract. Verify full experimental details before implementation.Compares untreated and surface-modified aluminas by IR probe molecules and reactions. The sodium-modified sample is reported to have fewer and weaker Lewis sites; catalytic response depends on the reaction. DOI: 10.1016/S0926-860X(97)00061-6
Evidence accessed: Institutional abstract. Verify full experimental details before implementation.Ni on sodium-neutralized silica–alumina: support acidity falls and acid-catalyzed cumene dealkylation decreases with Na; compare metal properties before assigning all changes to acidity. DOI: 10.1016/0021-9517(78)90147-1
Evidence accessed: Repository abstract. Verify full experimental details before implementation.Metal acetate salts poison cumene cracking over silica–alumina. Cation identity and loading matter; chemical neutralization and blocking are potential competing explanations. DOI: 10.1016/0021-9517(68)90016-X
Evidence accessed: Abstract. Verify full experimental details before implementation.Alkali acetates on silica, alumina and niobia are compared using acid–base probe reactions. Basicity responses vary with support; generating basicity does not itself quantify acidity loss. DOI: 10.1016/j.apcata.2006.02.013
Evidence accessed: Abstract. Verify full experimental details before implementation.Compares alkali-modified oxide supports in Knoevenagel condensation and kinetics; provides complementary basic-catalysis context rather than direct proof of alumina site neutralization. DOI: 10.1016/j.cattod.2008.08.023
Evidence accessed: Abstract. Verify full experimental details before implementation.NaOH treatment of ZSM-5 modifies porosity and acidity; the subsequent H-form exchange means the treated material is not simply a sodium-neutralized catalyst. Transport and framework changes confound activity comparisons. DOI: 10.1016/S0926-860X(01)00645-7
Evidence accessed: Article/abstract. Verify full experimental details before implementation.Na₂CO₃-treated H-ZSM-5 was examined for glycerol dehydration. Desilication, exchange and porosity changes distinguish this from a clean alkali-neutralization experiment. DOI: 10.1016/j.jcat.2018.07.036
Evidence accessed: Abstract. Verify full experimental details before implementation.Acidity tuning of HZSM-5 by neutralization titration for coke inhibition in n-dodecane cracking. Verify titrant, loading and quantitative results in the full text before adopting a protocol. DOI: 10.1016/j.apcata.2021.118278
Evidence accessed: Abstract / metadata. Verify full experimental details before implementation.Directly relevant to lignin-model HDO: sulfided NiMo and CoMo catalysts on K-modified γ-alumina were tested in a batch reactor at 523 K and reported hydrogen pressure of 5.5 MPa. Potassium decreased acidity and guaiacol conversion while shifting selectivity toward direct aromatic C–OH bond scission and hydrogenation. It also changed Mo coordination and increased the relative concentration of inactive NiAl₂O₄ and CoAl₂O₄ species. Thus the reaction outcome cannot be assigned to acidity alone; consult the paper for pressure basis and details. DOI: 10.1016/j.cattod.2017.07.015
Evidence accessed: institutional abstract; full experimental tables were not reviewed.Search date: 4 November 2026. Discovery used scholarly and publisher records across potassium-doped alumina, sodium-poisoned alumina, hydroxide-treated silica–alumina, supported metal catalysts and alkaline-treated zeolites. DOI-to-title pairs were checked against OpenAlex metadata; where available, publisher or repository abstracts informed the evidence summaries. This is a relevance-selected, non-exhaustive review, not a systematic review or a full-text review of all 25 papers.
Paper labels identify whether the experiment directly involves the support or is a confounded/adjacent comparison. “Direct” identifies relevance of the material or neutralization test, not proof of a unique atomic mechanism. Studies describing formation of basic sites or changes in activity are not treated as quantitative measurements of acid sites lost.