NiPS₃ Nanosheet–Graphene Composites as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

Abstract

Developing new electrocatalysts is essentially important for efficient water splitting to produce hydrogen. Two-dimensional (2D) materials provide great potential for high-performance electrocatalysts because of their high specific surface area, abundant active edges, and tunable electronic structure. Here, we report few-layer NiPS nanosheet-graphene composites for high-performance electrocatalysts for oxygen evolution reaction (OER). The pure NiPS nanosheets show an overpotential of 343 mV for a current density of 10 mA cm, which is comparable to that for IrO and RuO catalysts. More importantly, the NiPS nanosheet-graphene composites show significantly improved OER activity due to the synergistic effect. The optimized composite shows a very low overpotential of 294 mV for a current density of 10 mA cm, 351 mV for a current density of 100 mA cm, a small Tafel slope of 42.6 mV dec, and excellent stability. These overall performances are far better than those of the reported 2D materials and even better than those of many traditional materials even at a much lower mass loading of NiPS.

Engineering Ternary Pyrite‐Type CoPS Nanosheets with an Ultrathin Porous Structure for Efficient Electrocatalytic Water Splitting

“…[12][13][14]34,35] To get a deeper understanding of the OER process, a series of characterizations of CoPS UPNSs before and after OER were carried out, including XPS spectrum, Raman spectrum, XRD, and TEM. [12][13][14]34,35] To get a deeper understanding of the OER process, a series of characterizations of CoPS UPNSs before and after OER were carried out, including XPS spectrum, Raman spectrum, XRD, and TEM.…”

“…The PÀ O bond and SÀ O bond become dominant in the P 2p spectra and S 2p spectra ( Figure S13b and c) respectively, indicating electrochemical oxidation during the OER process. [12][13][14] Figure S13e shows the Raman shift of CoPS UPNSs before and after OER testing. [38,39] Another peak at 532.4 eV is assigned to the higher covalence of surface hydroxyls.…”

“…For example, Sun et al proposed the topotactic conversion preparation of various transition metal phosphides as water splitting electrocatalysts. [10][11][12][13][14] Density function theory (DFT) calculations have revealed that replacing S with the less electronegative P in the CoS 2 could tune the CoS 2 electronic structure to a more thermo-neutral hydrogen adsorption at the active sites and thus enhance HER activity. Very few catalysts can perform both HER and OER in wide pH ranges.…”

Metall‐Phosphor‐Trichalkogenide (MPCh3): von der Synthese zu aktuellen Energieanwendungen

“…[37,46,47,61,65] Optimierte Ni 0.95 Co 0.05 PS 3 -Nanoblätter,h ergestellt durch Festkçrperreaktion mit anschließender ultraschallunterstützter Exfoliation, zeigen ein Überpotential von 71 mV gegen RHE und einen Tafel-Anstieg von 77 mV dec À1 in 1.0 m KOH( Abbildung 4e-h). [37,46,47,61,65] Optimierte Ni 0.95 Co 0.05 PS 3 -Nanoblätter,h ergestellt durch Festkçrperreaktion mit anschließender ultraschallunterstützter Exfoliation, zeigen ein Überpotential von 71 mV gegen RHE und einen Tafel-Anstieg von 77 mV dec À1 in 1.0 m KOH( Abbildung 4e-h).…”

“…Der Degradationsgrad kann vom verwendeten Medium abhängen. [21,22,37,40,42,43,45,47,65,67,68] In Analogie zur HER hat MPSe 3 -Volumenmaterial ein geringeres Onset-Potential als MPS n ,j edoch sind die Ausbeuten bei weitem nicht konkurrenzfähig,u nd die Stabilitäti st sehr mangelhaft. Die XPS-Untersuchung des BiPS 4 -Materials zeigte eine vollständige ¾nderung seiner Zusammensetzung unter Komplettverlust des P. [21] Die MPSe 3 -Materialien waren in alkalischen Medien weniger stabil als in sauren, wobei FePSe 3 und MnPSe 3 jedoch den anderen Verbindungen überlegen waren und deshalb als die beiden interessantesten Vertreter der untersuchten Reihe gelten (Abbildung 4i,j).…”