Interfacial engineering of gallium indium phosphide photoelectrodes for hydrogen evolution with precious metal and non-precious metal based catalysts

Abstract

A nanoscale molybdenum disulfide (MoS2) film functions both as an effective protection layer and excellent hydrogen evolution catalyst for GaInP2 photocathodes.

Addressing the Stability Gap in Photoelectrochemistry: Molybdenum Disulfide Protective Catalysts for Tandem III–V Unassisted Solar Water Splitting

“…Molybdenum disulfide nanomaterials have been shown to stabilize a variety of singlejunction Si and III-V PEC systems, functioning as a hydrogen evolution reaction (HER) catalyst and protection layer. [9][10][11][12][13][14][15] Because of the promising performance in single-junction photocathodes, it is of interest to use MoS2 with tandem semiconductor systems to improve the stability during unassisted solar water splitting.…”

“…16 An MoS2 coating was deposited on the MoS2/pn-GaInAsP/pn-GaAs device (hereby known as MoS2/III-V) by sputtering a nominal 3.6 nm Mo metal film followed by a thermal partial sulfidization (Figure 1). [9][10][11] This MoS2 coating procedure is identical to that performed in a previous study on MoS2-coated GaInP2 phocathodes; X-ray photoelectron spectroscopy (XPS) demonstrated that the catalyst coating comprised a mixture of MoS2, metallic Mo, and MoOx. 9 In another work developing MoS2/n + p-Si photocathodes with a MoS2 deposition process utilizing a slightly higher sulfidization temperature but otherwise identical to that in this work, cross-sectional transmission electron microscopy (TEM) imaging demonstrated a thickness of ~5 nm, with MoS2 sheets residing on top of a thin metallic Mo layer.…”

“…Molybdenum disulfide nanomaterials have been shown to stabilize a variety of singlejunction Si and III-V PEC systems, functioning as a hydrogen evolution reaction (HER) catalyst and protection layer. [9][10][11][12][13][14][15] Because of the promising performance in single-junction photocathodes, it is of interest to use MoS2 with tandem semiconductor systems to improve the stability during unassisted solar water splitting.While most III-V-based unassisted water splitting devices to date have incorporated a Ga0.51In0.49P (hereafter GaInP2) (1.8 eV) top cell, device lifetimes have been limited to <100 h. 7,16 GaxIn1-xAsyP1-y (1.7 eV) has shown promise as a PV material and has been paired with a GazIn1-zAs bottom cell (1.1 eV) for efficient tandem PV systems, motivating efforts to incorporate GaxIn1-xAsyP1-y into PEC systems and investigate the stability of this quaternary top cell. [16][17][18][19] The composition of GaxIn1-xAsyP1-y (hereafter GaInAsP), nominally x ~ 0.68 and y ~ 0.34, gives the desired bandgap of 1.7 eV and a lattice constant matching that of GaAs.…”

Increasing Electrocatalytic Oxygen Evolution Efficiency through Cobalt‐Induced Intrastructural Enhancement and Electronic Structure Modulation

“…Among these, transition‐metal phosphides (TMPs) are considered to be one of the most studied electrocatalytic materials at present [23–25] . However, monometal TMPs usually have poor electroconductivities and inferior stabilities, thus significantly limiting their expected catalytic activities [26–28] . For this reason, multicomponent TMPs have been developed and have proven to be feasible alternatives for enhancing catalytic performance, both in theory and practice [3,29,30] .…”

“…[23][24][25] However, monometal TMPs usually have poor electroconductivities and inferior stabilities, thus significantly limiting their expected catalytic activities. [26][27][28] For this reason, multicomponent TMPs have been developed and have proven to be feasible alternatives for enhancing catalytic performance, both in theory and practice. [3,29,30] In NiÀ FeÀ P, for example, density functional theory (DFT) calculations have revealed that the electronic structure of the NiÀ P catalyst can be readily tuned with the help of extra Fe 3d states at the Fermi level, greatly reducing the charge transfer resistance and thus promoting its OER activity.…”