Environmentally-friendly preparation of natural hollow carbon spheres derived from a biomass puffball for in situ upgrading of lignin-derived vanillin

Biomass appears to be a potential candidate for the preparation of porous carbon materials with wide applications for catalytic fields due to its low price, green sustainability and natural hierarchical porous structure. Here, we designed a novel Ni x Cu y /BC catalyst with a unique hollow sphere structure derived from a biomass puffball, which exhibited a superior catalytic transfer hydrodeoxygenation of VAN to value-added MMP products with an ∼100% vanillin (VAN) conversion and over 88% selectivity of 2-methoxy-4-methylphenol (MMP) products in the absence of additional hydrogen. The good catalytic activity performance of the Ni x Cu y /BC catalysts was attributed to the NiCu alloy with a unique hollow sphere structure, high dispersion and electron transfer. Density functional theory (DFT) calculation results also indicated NiCu alloy as the main catalytic sites. This work not only provided a cheap and efficient hydrodeoxygenation catalyst for VAN hydrodeoxygenation, but also offered new insights for designing novel and unique biomass-based carbon materials for biomass utilizations or other widespread applications.