Engineering a built-in electric field in a wood-derived NiFeCo-LDH@NiFe heterojunction for enhanced bifunctional water splitting

Abstract

Optimizing the electronic structure is pivotal in augmenting the intrinsic catalyst activity. The fabrication of a rationally designed heterostructure is an effective approach to modulate the electronic landscape. In this context, we constructed self-supported metal-/wood-based electrocatalysts featuring a three-dimensional, layered and porous architecture. By utilizing NiFe alloy nanospheres as a bridging component to interconnect with NiFeCo-LDH, we established a robust heterojunction that is securely anchored onto a wood-derived substrate. The wood's natural 3D porous structure promotes active site exposure and gas release, while its hydrophilicity and the integration of the NiFe alloy with NiFeCo-LDH enhance the electrolyte transport and electron transfer, boosting the substrate's catalytic activity. This innovative construct leverages the synergistic effects at the metal–organic heterointerface, thereby enhancing electron transfer kinetics and catalytic efficiency in electrochemical applications. The synthesized NiFeCo-LDH@NiFe/CW catalyst, with an enhanced surface electron density, shows reduced oxygen intermediate adsorption energy and excellent bifunctional electrocatalytic performance with low overpotentials (90 mV for the OER and 70 mV for the HER) and long-term stability for over 24 hours. This work provides a new way for high-value utilization of wood materials.