Bifunctional Catalyst Derived from Sulfur-Doped VMoO_x Nanolayer Shelled Co Nanosheets for Efficient Water Splitting

Abstract

A novel sulfur-doped vanadium–molybdenum oxide nanolayer shelling over two-dimensional cobalt nanosheets (2D Co@S-VMoO x NSs) was synthesized via a facile approach. The formation of such a unique 2D core@shell structure together with unusual sulfur doping effect increased the electrochemically active surface area and provided excellent electric conductivity, thereby boosting the activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, only low overpotentials of 73 and 274 mV were required to achieve a current response of 10 mA cm–2 toward HER and OER, respectively. Using the 2D Co@S-VMoO x NSs on nickel foam as both cathode and anode electrode, the fabricated electrolyzer showed superior performance with a small cell voltage of 1.55 V at 10 mA cm–2 and excellent stability. These results suggested that the 2D Co@S-VMoO x NSs material might be a potential bifunctional catalyst for green hydrogen production via electrochemical water splitting.

A hybrid trimetallic–organic framework-derived N, C co-doped Ni–Fe–Mn–P ultrathin nanosheet electrocatalyst for proficient overall water-splitting

“…Then, the polarization curves were recorded at a lower scan rate of 2 mV s À1 to suppress the redox peak of Ni foam. The measured potentials were converted against RHE according to the Nernst equation 29,30 All the linear sweep voltammetry (LSV) curves were iR-corrected using the equation E corr ¼ E RHE À iR s , 29,31,32 where R s and E corr are the solution resistance and iR-corrected potential, respectively. The Tafel slopes were calculated from the corresponding polarization curves following the equation h ¼ b log j + a, 29 where h, j, and b are the overpotential, current density, and Tafel slope, respectively.…”

Defect and Interface Engineering of Three-Dimensional Open Nanonetcage Electrocatalysts for Advanced Electrocatalytic Oxygen Evolution Reaction

“…Splitting water via electricity is a promising strategy to effectively produce renewable hydrogen energy; however, inherently sluggish dynamics with a complicated four-electron transfer process for the oxygen evolution reaction (OER) proceeding at the anode demands a high overpotential to drive the reaction, resulting in large energy consumption and high cost. − It is difficult that the benchmark Ru/Ir-based catalysts meet large-scale practical applications due to their prohibitive costs, as well as disadvantageous environmental effects. − Currently, earth-abundant transition metal compounds, especially transition metal oxides (TMOs), have attracted increasing attention for serving as an alternative of Ru/Ir-based catalysts; however, most of these TMOs will exhibit limited OER activity because of unfavorable electronic structure and large electron transfer resistance. − With great endeavors devoted, the electrocatalytic performance of TMOs has been substantially improved; however, their performances are still unsatisfactory due to low intrinsic activity and limited active sites. − Rational combination of precious metals and TMOs via heterostructuring or doping could not only reduce the utilization of noble metals but also regulate the electronic properties of TMOs to boost the electrocatalytic reaction. − In addition, several strategies have also been proposed and applied for promoting the electrocatalytic OER activity of TMOs, including morphology regulation, interface engineering, phase control, heteroatom doping, and defect engineering. − Therein, interface engineering and defect engineering have been widely accepted as advanced pathways for tailoring surface and electronic properties at the atomic level. − On the one hand, rational interface engineering would create more accessible active sites, induce electronic and synergistic effects, and optimize surface chemical components. − On the other hand, the creation of surface defects would also exert remarkable influences on the binding strength between the intermediated species and defect sites, which is also essential to the OER activity. − However, simultaneous defect engineering and interface engineering in a TMO catalyst and a deep understanding of the structure–functional relationship are rarely reported.…”

Atomic Heterointerface Engineering of Ni2P‐NiSe2 Nanosheets Coupled ZnP‐Based Arrays for High‐Efficiency Solar‐Assisted Water Splitting

“…To further verify the enhanced HER and OER performance of the ZnP@Ni 2 P-NiSe 2 , we evaluated the electroactive surface area (ECSA) and electronic conductivity. The ECSA of the synthesized materials can be evaluated by double-layer capacitance (C dl ), which is measured by CV at different scan rates (20,40,60,80, and 100 mV s -1 ; Figure S19, Supporting Information). Figure 3g shows CV response of the synthesized materials at a scan rate of 20 mV s -1 , which reveals the largest rectangular area for the ZnP@Ni 2 P-NiSe 2 as compared to other materials.…”

“…Generally, nanocarbon allotropes are extensively utilized as potential supports; however, some challenges relating to insufficient stability and low interactions between carbon surface and active material restrict their practicality. [18] Therefore, several reports have nominated different suitable substrates derived from one-dimensional (1D) or 2D structures of pure metals [19,20] or their compounds (such as phosphides, carbides, and nitrides). [21,22] In this context, metal phosphides, such as nickel (Ni) and cobalt (Co) phosphide structures have attracted much attention.…”