Promotion effect of metal phosphides towards electrocatalytic and photocatalytic water splitting

Abstract

Hydrogen evolution from water splitting over semiconductors has been considered one of the most promising ways to address energy shortages and environmental pollution. Searching for low‐cost, highly efficient, and durable catalysts is the key to improve the hydrogen production rate. Expensive noble metals, such as Pt and Au, are generally loaded onto semiconductors to promote photocatalytic activity. Metal phosphides are promising candidates to replace noble metals in hydrogen generation via electrocatalytic or photocatalytic water splitting due to their low hydrogen‐producing overpotential, tunable electronic structure, high electrical conductivity, and low price. In this review article, the characteristics and synthetic methods of metal phosphides are briefly introduced, and the development of metal phosphides for electrocatalytic or photocatalytic water splitting is presented. Finally, the challenges and future directions of metal phosphides are discussed.

Progress and Perspectives in Photo‐ and Electrochemical‐Oxidation of Biomass for Sustainable Chemicals and Hydrogen Production

“…The high alkaline conditions promote the formation of Cd(OH) 2 /CdO on the surface which stabilizes the catalysts against photocorrosion and additionally facilitates the solubility of lignocellulose. The photocatalytic tests with α-cellulose as substrate resulted in an average quantum efficiency of 1.2%, at λ = 430 nm and the oxidation of the polysaccharide groups to carboxylic acids as confirmed by 13 C-NMR. [342] Utilizing this system, lignocellulose, including wood or paper could be reformed under light.…”

“…examples are run under very basic conditions (pH [13][14], to both preserve the metallic catalyst and assist the dehydrogenation steps. This is problematic for FDCA purification though, as it only precipitates at pH < 1, generating sizeable amounts of waste from the acidification of the solution at the end of the reaction.…”

“…[125] Fernández et al employed in situ FTIR and isotopically labeled glycerol ( 13 CH 2 OH 12 CHOH 13 CH 2 OH) to investigate the CC bond cleavage and CO 2 formation on Pt in acidic media. [120,126,127] They have found out that the terminal 13 CH 2 OH groups are easier to electro-oxidize and can happen at low potentials around 0.3 V RHE , while the mass production of 12 CO 2 from the central 12 CHOH group can only be observed above 1.2 V RHE . Li and Harrington covered in detail glycerol electro-oxidation mechanism through an overview of previous studies.…”

“…Nevertheless, up to now most of the reported semiconductors proven to produce H 2 upon water splitting do not display a positive enough valence band for carrying out the sluggish water oxidation. [10][11][12][13][14] Value-added oxidation reactions are a particularly attractive pathway forward to further reduce costs through a reduced energy consumption and added market value. As illustrated in Figure 1, biomass electrolysis as a viable alternative, substitutes the sluggish water oxidation with the thermodynamically more favorable organic molecule oxidation.…”

Effects of transition metal doping on electronic structure of metastable β-Fe2O3 photocatalyst for solar-to-hydrogen conversion

“…It is the best choice to achieve sustainable development, which has aroused increasing interest in solar energy. [6][7][8][9][10][11] However, due to the daily and seasonal fluctuations and uneven distribution of solar energy, its storage and utilization is still a huge challenge. 12 As new branches of chemistry, photocatalysis and photoelectrochemistry can continuously convert inexhaustible solar energy into storable chemical energy, and have broad application prospects in solar energy conversion and environmental protection.…”