Electrochemical Biomass Upgrading Coupled with Hydrogen Production under Industrial-Level Current Density.

Abstract

As promising hydrogen energy carrier, formic acid (HCOOH) plays an indispensable role in building a complete industry chain of a hydrogen economy. Currently, the biomass upgrading assisted water electrolysis has emerged as an attractive alternative for co-producing green HCOOH and H₂ in a cost-effective manner, yet simultaneously affording high current density and Faradaic efficiency (FE) still remains a big challenge. Here, the ternary NiVRu-layered double hydroxides (LDHs) nanosheet arrays for selective glycerol oxidation and hydrogen evolution catalysis are reported, which yield an industry-level 1 A cm^-2 at voltage of 1.933 V, meanwhile showing considerable HCOOH and H₂ productivities of 12.5 and 17.9 mmol cm^-2  h^-1 , with FEs of almost 80% and 96%, respectively. Experimental and theoretical results reveal that the introduced Ru atoms can tune the local electronic structure of Ni-based LDHs, which not only optimizes hydrogen adsorption kinetics for HER, but also reduces the reaction energy barriers for both the conversion of Ni^II into GOR-active Ni^III and carboncarbon (CC) bond cleavage. In short, this work highlights the potential of large-scale H₂ and HCOOH productions from integrated electrocatalytic system and provides new insights for designing advanced electrocatalyst for low-cost and sustainable energy conversion.