Controllable modification for adjacent circumstance controls cellulose conversion to ketols on Ni CCCs at particle levels

The metal immobilizing micro-circumstance is intensively relevant to its catalytic activity and selectivity. In order to obtain C 3,4 ketols by protection of C = O bonds against further hydrogenation, we proposed a promising strategy to modify adjacent circumstance for nickel complexes carbide catalysts (CCCs). The Sn promoted nickel CCCs exhibited high selectivity for cellulose conversion to C 3,4 ketols with the yield of 54.8%. The characterization results demonstrated the coordination environment of metals were reconstructed by C x N y species to form isolated nickel sites. The size-dependent electron transfer occurred when the sizes changed (from cluster to nanoparticles). This electron transfer facilitated promotion of the selectivity for C 3,4 ketols by protection of C O bonds against further hydrogenation. Combined with density functional theory calculations, the size-dependent electron transfer and Lewis base forming mechanism in Ni@C x N y structure were revealed. C x N y phases changed the electronic abundance of Ni sites and subsequently acted as Lewis base. Our work hinted that size of metallic catalysts should be optimized in specific loading circumstance to maximize the catalytic selectivity rather than simply chasing atomic efficiency.