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Abstract In this work, nanosheet-shaped CuS (NS CuS) is successfully grown on carbon cloth (CC) by a two-step route in combination with electrodeposition and hydrothermal treatment via in situ sulfidations of Cu 2 O and Cu with exposure to thiourea at 120 °C or 24 h. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry are performed to characterize the microstructure, morphology, composition, and crystal structure of the NS CuS CC samples. The electrochemical measurements demonstrate that the synthesized NS CuS CC electrocatalysts possess outstanding oxygen evolution reaction (OER) performance and superior long-term durability in 1 M KOH electrolyte. In particular, the NS CuS CC synthesized via the electrodeposition process at an applied current of 1.5 mA shows a low overpotential for the OER (358 mV at 10 mA/cm2), which is close to that of commercial IrO 2 (346 mV at 10 mA/cm2). The exceptional OER property is ascribed to the NS CuS having a large surface area to offer abundant reaction active sites and to the CC network structures supplying more ions and charge transfer channels during the electrocatalytic process. [ABSTRACT FROM AUTHOR]

Although cobalt pyrophosphate (Co2P2O7) has shown promise as a potential electrocatalyst for the oxygen evolution reaction (OER), its electrocatalytic activity for the oxygen reduction reaction (ORR) has rarely been explored. In this work, a novel composite catalyst with in situ grown Co2P2O7 on nitrogen-doped graphene nanosheets (Co2P2O7/N-rGO) was fabricated by a facile one-step pyrolysis method. Pyrolysis temperature was found to have a significant effect on the morphology, structure and ORR performance of the composites. The catalyst fabricated at 800 °C (Co2P2O7/N-rGO-800) presented ultrasmall Co2P2O7 nanocrystals (below 5 nm) anchored on N-rGO and the highest pyridinic-N proportion. Benefiting from the full exposure of active sites on the ultrasmall Co2P2O7 nanocrystals, abundant pyridinic-N species and the synergistic effect of Co2P2O7 and N-doped graphene, optimized Co2P2O7/N-rGO-800 not only demonstrates excellent ORR catalytic activity with a positive cathodic peak potential (0.823 V vs. 0.833 V of the commercial Pt/C catalyst), but also shows superior durability and methanol crossover resistance to Pt/C in alkaline solution. In addition, the composite catalyst also exhibits reasonable oxygen evolution reaction (OER) performance and impressive OER stability in KOH solution. These findings suggest that the Co2P2O7/N-rGO catalysts may be promising candidates as oxygen electrocatalysts for future energy conversion applications. [ABSTRACT FROM AUTHOR]

Here, we demonstrate the synthesis of sheet-shaped Co2P grown on carbon cloth (sheet-shaped Co2P-CC) through a facile route. Electrochemical measurements indicated that sheet-shaped Co2P-CC with a loading of 0.6 mg cm−2 Co2P (denoted Co2P-CC-0.6) exhibits exceptional electrocatalytic activity in the hydrogen evolution reaction (HER), with an overpotential of 94 mV at a current density of 10 mA cm−2 and a small Tafel slope of 80 mV decade−1 in 1 M KOH. Similarly, sheet-shaped Co2P-CC-0.6 was also found to be an excellent electrocatalyst for the HER in 0.5 M H2SO4 and in 0.5 M phosphate buffer solution (PBS), with overpotentials of 95 and 231 mV at a current density of 10 mA cm−2, respectively. Sheet-shaped Co2P has a large surface area, meaning that it can provide a relatively large number of active sites on its surface, and CC is an highly conductive substrate that, when used in conjunction with Co2P, can enhance the conductivity of the electrocatalyst. These outstanding results show that sheet-shaped Co2P-CC could be an excellent candidate for a highly efficient electrocatalyst. [ABSTRACT FROM AUTHOR]