Water-induced Brønsted acidity and metal-acid synergy over Co@CoP catalysts for hydrolytic hydrogenolysis of furfural to 1,4-pentanediol

Water can dissociate on the CoP shell with the formation of H - -Co δ+ -P-O-H + intimate metal-acid sites. • Intimate metal-acid bifunctional sites effectively catalyze the hydrodeoxygenation of furfural to 2-methylfuan. • Brønsted acid sites promote hydrolysis and ring-opening hydrogenolysis of 2-methylfuran to yield 1,4-pentanediol. • Co@CoP catalyst exhibits excellent stability and high activity for the hydrodeoxygenation of various biomass-derived feedstocks. Transition metal phosphides represent promising metal-acid bifunctional catalysts for hydrogenation reactions. However, the origin of the acidity of metal phosphides and their synergistic effects with metallic sites remain poorly understood. Herein, a highly efficient core-shell Co@CoP catalyst prepared via controlled phosphidation of cobalt carbonate was developed for the one-pot transformation of furfural to 1,4-pentanediol. The metallic Co core accelerates active hydrogen transfer, while the CoP shell enables water dissociation to form intimate H - –Co δ+ –P–O–H + metal-acid sites. While the metal-acid bifunctional sites synergistically catalyze the efficient hydrodeoxygenation of furfural to 2-methylfuran intermediate, the Brønsted acid sites on CoP further selectively activate the C–O–C bond of 2-methylfuran, facilitating hydrolysis and ring-opening hydrogenolysis. A 1,4-pentanediol yield of 92.2% is achieved under mild conditions, with excellent cycling stability and applicability for various biomass-derived feedstocks. The disclosed water-engineered Brønsted acidity over metal phosphides provides a fundamental basis for the rational design of bifunctional catalysts for biomass valorization. Co@CoP catalyst enables water dissociation to form intimate H - –Co δ+ –P–O–H + metal-acid sites. While the metal-acid bifunctional sites synergistically catalyze the efficient hydrodeoxygenation of furfural to 2-methylfuran intermediate, the Brønsted acid sites on CoP further selectively activate the 2-methylfuran, facilitating hydrolysis and ring-opening hydrogenolysis. Download: Download high-res image (277KB) Download: Download full-size image