Electrochemical oxidation of biomass-derived platform molecules can enable the production of value-added oxygenated commodity chemicals under mild conditions in a distributed fashion using renewable electricity; however, very few efficient, robust, and inexpensive electrocatalysts are available for such electrochemical oxidation. Here we demonstrate that earth-abundant NiFe layered double hydroxide (LDH) nanosheets grown on carbon fiber paper can efficiently catalyze the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) at the anode of an electrochemical cell. A near-quantitative yield of FDCA and 99.4% Faradaic efficiency of HMF conversion under ambient conditions can be achieved in the electrochemical process. HMF has a higher rate of oxidation than water and can act as an alternative anodic reaction for alkaline H 2 evolution in water-splitting cells. As the first report on using bimetallic metal hydroxide/oxide catalysts for electrochemical oxidation of HMF, this work opens up opportunities in electrochemical devices to simultaneously produce building-block chemicals from biomassderived molecules and clean H 2 fuels under ambient conditions with earth-abundant materials.

Biomass is increasingly perceived as a renewable resource rather than as an organic solid waste today, as it can be converted to various chemicals, biofuels, and solid biochar using modern processes. In the past few years, pyrolysis has attracted growing interest as a promising versatile platform to convert biomass into valuable resources. However, an efficient and selective conversion process is still difficult to be realized due to the complex nature of biomass, which usually makes the products complicated. Furthermore, various contaminants and inorganic elements (e.g., heavy metals, nitrogen, phosphorus, sulfur, and chlorine) embodied in biomass may be transferred into pyrolysis products or released into the environment, arousing environmental pollution concerns. Understanding their behaviors in biomass pyrolysis is essential to optimizing the pyrolysis process for efficient resource recovery and less environmental pollution. However, there is no comprehensive review so far about the fates of chemical elements in biomass during its pyrolysis. Here, we provide a critical review about the fates of main chemical elements (C, H, O, N, P, Cl, S, and metals) in biomass during its pyrolysis. We overview the research advances about the emission, transformation, and distribution of elements in biomass pyrolysis, discuss the present challenges for resource-oriented conversion and pollution abatement, highlight the importance and significance of understanding the fate of elements during pyrolysis, and outlook the future development directions for process control. The review provides useful information for developing sustainable biomass pyrolysis processes with an improved efficiency and selectivity as well as minimized environmental impacts, and encourages more research efforts from the scientific communities of chemistry, the environment, and energy.