Crystalline Copper Phosphide Nanosheets as an Efficient Janus Catalyst for Overall Water Splitting

Abstract

Hydrogen is essential to many industrial processes and could play an important role as an ideal clean energy carrier for future energy supply. Herein, we report for the first time the growth of crystalline CuP phosphide nanosheets on conductive nickel foam (CuP@NF) for electrocatalytic and visible light-driven overall water splitting. Our results show that the CuP@NF electrode can be used as an efficient Janus catalyst for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). For OER catalysis, a current density of 10 mA/cm requires an overpotential of only ∼320 mV and the slope of the Tafel plot is as low as 54 mV/dec in 1.0 M KOH. For HER catalysis, the overpotential is only ∼105 mV to achieve a catalytic current density of 10 mA cm. Moreover, overall water splitting can be achieved in a water electrolyzer based on the CuP@NF electrode, which showed a catalytic current density of 10 mA/cm under an applied voltage of ∼1.67 V. The same current density can also be obtained using a silicon solar cell under ∼1.70 V for both the HER and the OER. This new Janus CuP@NF electrode is made of inexpensive and nonprecious metal-based materials, which opens new possibilities based on copper to exploit overall water splitting for hydrogen production. To the best of our knowledge, such high performance of a copper-based water oxidation and overall water splitting catalyst has not been reported to date.

Remarkable Improvement in Water Oxidation Catalysis by Moderate Heat Treatment of a Crystalline Silver‐Based Thin Film Developed In‐Situ From Silver‐ions in Acetate Solution

“…This understanding is quite rational. The similar phenomenon was observed in previous reports . Figure S10 (in the Supporting Information) shows the high‐resolution XPS spectra of Ag3d.…”

“…Metal oxides involving Ag–O group are versatile materials and have been intensively pursued for promising application in oxidation catalysis,, sensors, fuel cells, all optical switching devices and optical data storage systems . Since both copper and silver are in the same group of periodic table, it is expected that like copper oxides (Cu 2 O and CuO), silver oxides (Ag 2 O and AgO) based materials also could be active as electrocatalysts for water oxidation. In line with this expectation, it is very surprising to find out that silver‐based films have been rarely reported and explored as an electrocatalysts for water oxidation compared to copper and other two well‐explored noble metals, e. g. Ru and Ir, although silver‐based materials have been shown to be photocatalyst for this process ,.…”

Cu3P/CuO Core‐Shell Nanorod Arrays as High‐Performance Electrocatalysts for Water Oxidation

“…To gain a deeper insight into the core‐shell structure of Cu−Cu 3 P/CuO, this electrode was further analyzed by X‐ray photoelectron spectroscopy (XPS) (Figure a–c). The Cu 2p 3/2 and Cu 2p 1/2 peaks at 932.6 and 952.6 eV (Figure a) and the P 2p peak at 129.6 eV (Figure b) indicate the retention of Cu 3 P core in Cu 3 P/CuO as compared with the XPS spectra of Cu−Cu 3 P (Figures S3a and S3b) ,. However, the intensities of the Cu 2p peaks arising from Cu 3 P were significantly decreased after electrochemical oxidation, along with the appearance of two new peaks for Cu 2p at 933.8 (2p 3/2 ) and 953.8 eV (2p 1/2 ) and the disappearance of the oxidized Cu−P signals at 934.5 (Cu 2p 3/2 ) and 954.7 eV (Cu 2p 1/2 ).…”

V4P6.98/VO(PO3)2 as an Efficient Non‐Noble Metal Catalyst for Electrochemical Hydrogen Evolution in Alkaline Electrolyte

“…[1] Electrocatalytic water splitting for hydrogen production shows great potential for developing hydrogen as a new energy source owning to its low-energy consumption and high-purity products. [6,[30][31][32][33][34] According to previous research, P atoms are electronegative and can withdraw electron density from metal atoms and act as a proton carrier in HER catalysts, leading to high catalytic activity. The oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) were two essential part of overall water-splitting process.…”

“…To our knowledge, only Fe 0.5 V 0.5 composites, CoÀ V hydr(oxy)oxide, and NiÀ V double-layered hydroxides have shown high activity as OER catalysts. [6,[30][31][32][33][34] According to previous research, P atoms are electronegative and can withdraw electron density from metal atoms and act as a proton carrier in HER catalysts, leading to high catalytic activity. [27][28][29] Recently, phosphide catalysts (such as FeP x , Ni x P y , Co x P y , MoP x , WP x , and Cu 3 P) have shown great potential for replacing noble metals in electrocatalytic water splitting for hydrogen production.…”