Nickel-Vanadium Layered Double Hydroxides for Efficient and Scalable Electrooxidation of 5-Hydroxymethylfurfural Coupled with Hydrogen Generation

Electrocatalytic water splitting driven by renewable energy is a potential approach to obtain green hydrogen. However, the relatively high overpotential of anodic oxygen evolution reaction (OER) is one of the main obstacles hindering the widespread popularity of water electrocatalysis technology. To this end, electrochemical hydrogen-evolution coupled with the oxidation of biomass derived platforms, such as replacing OER with thermodynamically favorable 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR), provides an efficient strategy to lower energy utilization and co-producing valuable organic oxygenates. For instance, 2,5-furandicarboxylic acid (FDCA) is emerging as an important and value-added industrial chemical obtained from HMFOR, which can be used as the monomer of various sustainable bioplastics (e.g., polyesters, polyamides). Great efforts have been devoted to this arena on electrocatalyst engineering for better activity and product selectivity. However, less work has focused on the process scalability of HMFOR to FDCA. Here, we report a simple hydrothermal method to fabricate an array-structured nickel-vanadium layered double hydroxides (NiV-LDH) growth on nickel foam matrix, demonstrating large-sized (6 cm × 10 cm) synthesis of self-supported electrode. The as-prepared material is active and efficient for HMFOR, achieving 100 mA∙cm −2 of current density at 1.52 V vs. reversible hydrogen electrode (RHE) with 94.6% of Faradaic efficiency and 89.1% of yield to FDCA. Compared to traditional water splitting, replacing OER with HMFOR improves the counterpart hydrogen production rate by two-times. As proof-of-concept, we demonstrate the continuous and scalable HMFOR using a low-cost and membrane-free flow reactor system with electrode area of 49.5 cm 2 . Under a constant current of 10 A, this system achieves high HMF single-pass conversion (94.8%), high FDCA concentration (~186.8 mmol∙L −1 ), and high FDCA selectivity (98.5%) using 200 mmol∙L −1 of HMF feedstock at a flow rate of 3.62 mL∙min −1 . Finally, gram-scale FDCA (119.5 g) can be obtained with hydrogen production using water electrolysis technology. This work highlights that catalyst design and system engineering should be coupled in the future rather than continuing in parallel directions. Download: Download high-res image (66KB) Download: Download full-size image