Kinetics and mechanistic insights into selective hydrogenation of furfural to furfuryl alcohol over Ni-Ga intermetallics

Furfural was mainly used to produce furfuryl alcohol, which is a monomer of furan resins with a global market of similar to$0.3 billion/year. Industrial production of furfuryl alcohol is via selective hydrogenation over toxic copper chromate under harsh conditions. Therefore, the search for active and non-toxic alternatives is highly desired. Here, kinetics studies revealed an inhibitive effect caused by strong furfural adsorption on Ni-based catalysts, resulting in sites blocking and undesired ring hydrogenation. Such an inhibitive effect can be alleviated over Ni-Ga intermetallic surfaces by tuning the Ni coordination number, from which the Ni1Ga1 showed markedly enhanced furfuryl alcohol yield (similar to 99%) at milder conditions comparing to the referred Ni catalyst. It is found that isolated Ni sites by Ga on the Ni1Ga1 enabled a tilted adsorption configuration through the carbonyl of furfural. In contrast, the stronger flat-lying adsorption of furfural was favored on the contiguous Ni sites of the referred catalyst.