Atomically thin photoanode of InSe/graphene heterostructure

Abstract

Achieving high-efficiency photoelectrochemical water splitting requires a better understanding of ion kinetics, e.g., diffusion, adsorption and reactions, near the photoelectrode’s surface. However, with macroscopic three-dimensional electrodes, it is often difficult to disentangle the contributions of surface effects to the total photocurrent from that of various factors in the bulk. Here, we report a photoanode made from a InSe crystal monolayer that is encapsulated with monolayer graphene to ensure high stability. We choose InSe among other photoresponsive two-dimensional (2D) materials because of its unique properties of high mobility and strongly suppressing electron–hole pair recombination. Using the atomically thin electrodes, we obtained a photocurrent with a density >10 mA cm−2 at 1.23 V versus reversible hydrogen electrode, which is several orders of magnitude greater than other 2D photoelectrodes. In addition to the outstanding characteristics of InSe, we attribute the enhanced photocurrent to the strong coupling between the hydroxide ions and photo-generated holes near the anode surface. As a result, a persistent current even after illumination ceased was also observed due to the presence of ions trapped holes with suppressed electron-hole recombination. Our results provide atomically thin materials as a platform for investigating ion kinetics at the electrode surface and shed light on developing next-generation photoelectrodes with high efficiency.

Incorporation of Sulfate Anions and Sulfur Vacancies in ZnIn2S4 Photoanode for Enhanced Photoelectrochemical Water Splitting

“…Photoelectrochemical (PEC) water splitting provides a promising strategy to capture and store abundant solar energy influx by hydrogen production. [1][2][3] The bottleneck in the PEC process is the four-electron participating oxygen evolution reaction (OER) that occurs on the surface of photoanode. [4] Thus, it is crucial to develop a highly efficient photoanode to achieve solar water slitting.…”

Rotation Tunable Type‐I/Type‐II Band Alignment and Photocatalytic Performance of g‐C3N4/InSe van der Waals Heterostructure

“…[15,16,18,19] Furthermore, g-C 3 N 4based HSs [33][34][35] and InSe-based HSs have been extensively fabricated in experiments. [36][37][38] In this respect, it is possible to synthesize the CNIS HSs with the progress of experimental preparation technology. In the meanwhile, it is interesting to synthesize the CNIS HSs based on theoretical study herein.…”

Core–Shell Photoanodes for Photoelectrochemical Water Oxidation

“…With monolayer core and shell, this is an extreme case of core–shell structure. [ 87 ] The atomically thin electrode exhibited a high current density of >10 mA cm –2 at 1.23 V RHE . The performance was ascribed to the strong coupling between hydroxide ions and photogenerated holes near the photoanode surface.…”