Metallic Transition Metal Selenide Holey Nanosheets for Efficient Oxygen Evolution Electrocatalysis

Abstract

Catalysts for oxygen evolution reaction (OER) are pivotal to the scalable storage of sustainable energy by means of converting water to oxygen and hydrogen fuel. Designing efficient electrocatalysis combining the features of excellent electrical conductivity, abundant active surface, and structural stability remains a critical challenge. Here, we report the rational design and controlled synthesis of metallic transition metal selenide NiCoSe-based holey nanosheets as a highly efficient and robust OER electrocatalyst. Benefiting from synergistic effects of metallic nature, heteroatom doping, and holey nanoarchitecture, NiCoSe holey nanosheets exhibit greatly enhanced kinetics and improved cycling stability for OER. When further employed as an alkaline electrolyzer, the NiCoSe holey nanosheet electrocatalyst enables a high-performing overall water splitting with a low applied external potential of 1.68 V at 10 mA cm. This work not only represents a promising strategy to design the efficient and robust OER catalysts but also provides fundamental insights into the structure-property-performance relationship of transition metal selenide-based electrocatalytic materials.

Controllable 1D and 2D Cobalt Oxide and Cobalt Selenide Nanostructures as Highly Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…The ECSAs of cobalt‐based catalysts were obtained by CV to measure the double‐layer capacitance from 1.00 to 1.10 V (vs. RHE). According to reports in the literature, we calculated the TOF by hypothesizing that every transition‐metal atom was involved in catalysis [Eq. ]: …”

Colloids of Holey Gd2O3 Nanosheets Converted from Exfoliated Gadolinium Hydroxide Layers

“…While some attempts have been made very recently to fabricate porous 2D materials and demonstrate their promising utility in molecular separation, energy storage, and conversion, which combines the advantageous aspects of two‐dimensional and porous materials, most have involved graphene materials that are easily processable using conventional techniques and processes . By contrast, there have been few reports of in‐plane mesoporous structures in intractable 2D metal oxide layers, and the development of such strategies is a significant challenge due to lack of synthetic methodology. Along with providing insight into the conversion behavior of the 2D‐nanostructured material, this confinement strategy therefore offers a synthetic route to produce a colloidal suspension of holey nanosheets of crystalline Gd 2 O 3 that can be used to fabricate a thin and porous film through wet‐coating deposition methods.…”

Heterogeneous Molten Salt Design Strategy toward Coupling Cobalt–Cobalt Oxide and Carbon for Efficient Energy Conversion and Storage

“…The result suggests that the hydroxyl and epoxy are broken down to form the bridged COCo bonds in CoO x @ GCS⊃Co (Figure 2f). [36] Figure 3e displays OH − ions absorbed on GC with Co modifying, is more stable than on pure GC. Based on the above results of the Raman spectra and FTIR, we may conclude that strong electronic interactions do occur between CoO x , Co, and GCS via the bridged bonds in the CoO x @GCS⊃Co.…”

“…The Raman spectra and Fourier transform infrared spectroscopy (FTIR) were performed to further detect the bond structure. [34][35][36] The Tafel slope versus overpotential for all catalysts is plotted in Figure S18 (Supporting Information). The perks at 1345 and 1579 cm −1 are the characteristic peaks of the D and G bands from graphitic carbon (Figure 2e).…”

“…(Figures S16a and S17, Supporting Information). The superior electrocatalytic activities for OER and HER of CoO x @GCS⊃Co can be ascribed to the following features: 1) strong bridged bonds and abundant oxygen vacancies boost the electrical conductivity and provide more exposed active sites, which kinetically accelerate the electrocatalytic reaction; [34][35][36] 2) the GCS matrix can effectively protect the cobalt-based species from undergoing dissolution, significantly improving the stability of catalyst. [34][35][36] The Tafel slope versus overpotential for all catalysts is plotted in Figure S18 (Supporting Information).…”