Efficiently selective C(O-)-C bond cleavage for full lignocellulose upgrading coupled with energy-saving hydrogen production by Ir single-atom electrocatalyst

The valorization of full lignocellulose is of considerable relevance for the simplification of native biomass refining and environmental preservation. Here, its complex compositions (carbohydrate and lignin derivatives) with C(O-)-C units were convergently upgraded into relatively single carboxylic acids with high yields (up to 99%) via oxidative cleavage by Ir single-atom electrocatalysts (Ir-NiFeO@NF). Theoretical calculations revealed that single Ir atoms helped accelerate the nucleophilic reaction by promoting the adsorption of reactants and the generation of active sources (OH*). Ir-NiFeO@NF demonstrated dual functionality by outperforming not only lignocellulose oxidation (≤ 1.35 VRHE) but also H2 evolution (26 mV), resulting in an overall cell that required only 1.33 VRHE at 10 mA cm−2. As a proof-of-concept effort, the lignocellulosic cell went forward to upgrade black liquor, saving 11 kWh of energy compared to commercial water electrolysis for making 1 kg of H2. This work will stimulate the advancement of comprehensively economic and sustainable biomass refining and fuel generation.