Modulating Surface Electron Density of Heterointerface with Bio‐Inspired Light‐Trapping Nano‐Structure to Boost Kinetics of Overall Water Splitting

Abstract Herein, inspired by natural sunflower heads’ properties increasing the temperature of dish‐shaped flowers by tracking the sun, a novel hybrid heterostructure (MoS 2 /Ni 3 S 2 @CA, CA means carbon nanowire arrays) with the sunflower‐like structure to boost the kinetics of water splitting is proposed. Density functional theory (DFT) reveals that it can modulate the active electronic states of NiMo atoms around the Fermi‐level through the charge transfer between the metallic atoms of Ni 3 S 2 and MoMo bonds of MoS 2 to boost overall water splitting. Most importantly, the finite difference time domain (FDTD) could find that its unique bio‐inspired micro‐nano light‐trapping structure has high solar photothermal conversion efficiency. With the assistance of the photothermal field, the kinetics of water‐splitting is improved, affording low overpotentials of 96 and 229 mV at 10 mA cm −2 for HER and OER, respectively. Moreover, the Sun‐MoS 2 /Ni 3 S 2 @CA enables the overall alkaline water splitting at a low cell voltage of 1.48 and 1.64 V to achieve 10 and 100 mA cm −2 with outstanding catalytic durability. This study may open up a new route for rationally constructing bionic sunflower micro‐nano light‐trapping structure to maximize their photothermal conversion and electrochemical performances, and accelerate the development of nonprecious electrocatalysts for overall water splitting.