Photoelectrochemical Activity of Layered Metal Phosphorous Trichalcogenides for Water Oxidation

Abstract

Abstract2D layered materials are currently one of the most explored materials in developing efficient and stable photoelectrocatalysts in energy conversion applications. Some of the 2D metal phosphorus chalcogenides (M2P2X6 or plainly MPX3) have been reported to be useful catalysts for water splitting. Herein, the photoresponsivity of a series of synthesized M2P2X6 (M2+ = Mn, Fe, Co, Zn, Cd; X = S, Se), tested for the oxygen evolution reaction (OER) region in alkaline media, with excitation wavelengths from 385 to 700 nm, is reported. The experimentally determined optical bandgaps of the MPX3 materials range from 1.5 eV for FePSe3 to 3.7 eV for ZnPS3. At +1.23 V versus reversible hydrogen electrode (RHE), the photoelectrochemical (PEC) activity in the OER region of MnPSe3 exhibits superior performance, while the exfoliation of CoPS3 improves its PEC activity up to double in contrast with its bulk counterpart. The influence of the substrate (glassy carbon (GC), indium tin oxide (ITO), and aluminum‐doped zinc oxide (AZO)) and applied potential is also studied. Exfoliated CoPS3 reaches a photoresponsivity of up to 0.6 mA W‐1 under 450 nm excitation wavelength and at +1.23 V versus RHE in alkaline electrolyte.

Synthesis of Magnesium Phosphorous Trichalcogenides and Applications in Photoelectrochemical Water Splitting

“…The potential of the MgPX 3 materials as photoanodes, in particular MgPSe 3 , is clearly evident, even compared to other MPX 3 materials or other 2D materials, as shown in Table S4, Supporting Information. In the MPX 3 family and comparing the performance on the same substrate (GC) and light source (420 nm), MgPSe 3 achieves a photocurrent density of 1.6 mA cm −2 , while values of 1.1 and 0.17 mA cm −2 were registered for MgPS 3 and exfoliated CoPS 3 , [ 21 ] respectively. Moreover, under the same experimental conditions as MgPSe 3 , a photocurrent density of ≈0.55 mA cm −2 was achieved by Pd 3 (PS 4 ) 2 .…”

“…[ 8,13 ] MPX 3 are semiconductors with a bandgap ranging from 1.3 up to 3.5 eV, direct or indirect, [ 8,13 ] suitable for optoelectrical devices [ 14,15 ] and photoelectrocatalysis. [ 15–21 ] The most intensively recently studied MPX 3 have been Mn, Fe, Co, and Ni based due to their magnetic properties and promising performance in water‐splitting reactions. [ 10,22–24 ]…”

Engineering van der Waals Materials for Advanced Metaphotonics

“…Recently, an emerging multielement 2D layered material is metal phosphorus trichalcogenides (MPTs), − which is one of the van der Waals layered materials first discovered in the late 19th century by Friedel and Ferrand. The framework layers of [P 2 S 6 ] 4– or [P 2 Se 6 ] 4– are weakly bonded to metal cations (M II or M I M III ) through van der Waals interactions.…”

Self-Enhancing Photoelectrochemical Properties in van der Waals Ferroelectric CuInP2S6 by Photoassisted Acid Hydrolysis

“…Numerous theoretical studies predicted that monolayer MPX 3 materials possess suitable band edge levels straddling the hydrogen and oxygen evolution potentials, satisfying the thermodynamic requirements for water splitting. Moreover, a wide choice of metal cations may endow the materials with versatile ferroelectric and ferromagnetic properties, − which could combine with the semiconductor character of these materials to modulate the PEC performance by additional degrees of freedom. , …”