The telescopic conversion of glucose to fructose and then 5-hydroxymethylfurfural (5-HMF), the latter a potential, bio-derived platform chemical feedstock, has been explored over a family of bifunctional sulfated zirconia catalysts possessing tuneable acid-base properties. Characterisation by acid-base titration, XPS, XRD and Raman reveal that submonolayer SO 4 coverages offer the ideal balance of basic 10 and Lewis/Brönsted acid sites required to respectively isomerise glucose to fructose, and subsequently dehydrate fructose to 5-HMF. A constant acid site normalised turnover frequency is observed for fructose dehydration to 5-HMF, confirming a common Brönsted acid site is responsible for this transformation. 65 110 stabilise. pH measurements on aqueous catalyst suspensions were performed by adding 0.1g of each catalyst to 20 ml of deionized water and stirring at room temperature. After 30 min the solution pH was measured using a Jenway 3305 pH meter.

The grafting and sulfation of zirconia conformal monolayers on SBA-15 to create mesoporous catalysts of tunable solid acid/base character is reported. Conformal zirconia and sulfated zirconia (SZ) materials exhibit both Brönsted and Lewis acidity, with the Brönsted:Lewis acid ratio increasing with film thickness and sulfate content. Grafted zirconia films also exhibit amphoteric character, whose Brönsted:Lewis acid site ratio increases with sulfate loading at the expense of base sites. Bilayer ZrO 2 /SBA-15 affords an ordered mesoporous material with a high acid site loading upon sulfation and excellent hydrothermal stability. Catalytic performance of SZ/SBA-15 was explored in the aqueous phase conversion of glucose to 5-HMF, delivering a threefold enhancement in 5-HMF productivity over non-porous SZ counterparts. The co-existence of accessible solid basic/Lewis acid and Brönsted acid sites in grafted SZ/SBA-15 promotes the respective isomerization of glucose to fructose and dehydration of reactively-formed fructose to the desired 5-HMF platform chemical.

Highlights  High OSCs' oxide supports promote CO-enriched syngas production of Rh-catalysed DRM  Low carbon deposition was revealed, increasing in the order Rh/CZ

Here we describe a simple route to creating conformal sulphated zirconia monolayers throughout an SBA-15 architecture that confers efficient acid-catalysed one-pot conversion of glucose to ethyl levulinate.