A metal oxide supported palladium catalyst comprised of a -Bi.sub.2O.sub.3/Bi.sub.2Sn.sub.2O.sub.7 hetero-junction catalyst support and palladium was developed. The catalyst was synthesized using a sol-gel technique as a nanocrystalline structure. In the presence of fluorene, an oxidant and ultraviolet irradiation, the catalyst converts the hydrocarbon to a mixture of fluorenol/fluorenone oxidation products. The close proximity between -Bi.sub.2O.sub.3 and Bi.sub.2Sn.sub.2O.sub.7 heterojunction phases in the catalyst is thought to be responsible for the efficient charge separation and catalytic activity. An indirect chemical probe method using active species scavengers elucidated that the photo-oxidation mechanism proceeds via holes and superoxide radical (O.sub.2..sup.) moieties.

Disclosed are methods for synthesizing an ester or a carboxylic acid from an organic alcohol. To form the ester one reacts, in the presence of oxygen gas, the alcohol with methanol or ethanol. This reaction occurs in the presence of a catalyst comprising palladium and a co-catalyst comprising bismuth, tellurium, lead, cerium, titanium, zinc and/or niobium (most preferably at least bismuth and tellurium). Alternatively that catalyst can be used to generate an acid from that alcohol, when water is also added to the reaction mix.

A metal loaded catalyst comprises a support and main active metal components and optional auxiliary active metal components, wherein the main active metal components are elementary substances and obtained by ionizing radiation reducing precursors of main active metal components. The catalyst can be widely used in the catalytic reactions of petrochemistry industry with high activity and selectivity. The catalyst can be used directly without being reduced preliminarily by hydrogen.

An oxidation catalyst is described for treating an exhaust gas produced by a diesel engine comprising a catalytic region and a substrate, wherein the catalytic region comprises a catalytic material comprising: bismuth (Bi), antimony (Sb) or an oxide thereof; a platinum group metal (PGM) selected from the group consisting of (i) platinum (Pt), (ii) palladium (Pd) and (iii) platinum (Pt) and palladium (Pd); and a support material, which is a refractory oxide: wherein the platinum group metal (PGM) is supported on the support material; and wherein the bismuth (Bi), antimony (Sb) or an oxide thereof is supported on the support material and/or the refractory oxide comprises the bismuth, antimony or an oxide thereof.

Disclosed are methods for synthesizing an ester or a carboxylic acid from an organic alcohol. To form the ester one reacts, in the presence of oxygen gas, the alcohol with methanol or ethanol. This reaction occurs in the presence of a catalyst comprising palladium and a co-catalyst comprising bismuth, tellurium, lead, cerium, titanium, zinc and/or niobium (most preferably at least bismuth and tellurium). Alternatively that catalyst can be used to generate an acid from that alcohol, when water is also added to the reaction mix.