2D/2D Black Phosphorus/Nickel Hydroxide Heterostructures for Promoting Oxygen Evolution via Electronic Structure Modulation and Surface Reconstruction

Abstract

as one crucial technology for hydrogen production, has received intensive attention in recent years. The current progress, however, is still far away from industrial applications. The major concerns are associated with electrocatalysts, particularly for the half-reaction, oxygen evolution reaction (OER). An ideal catalyst toward OER should manifest a high catalytic efficiency but a low material cost. Compared to the dominate noble-metal-based electrocatalysts, transition metal compounds are expected to be promising candidates to replace noble metals, ascribed to their low production costs and comparable catalytic properties. [2] Among these, nickel (Ni)-based hydroxides have been regarded as one of the most active OER catalysts, particularly in alkaline electrolytes. [3] The catalytic property of the pristine nickel hydroxide (Ni(OH) 2 ), however, is yet far from satisfactory, [4] and further structural or chemical optimization is always demanded for promoting its OER performance. To date, several strategies have been employed for enhancing the catalytic performance of Ni(OH) 2 catalyst, including i) manipulating the size or dimensionality for more active sites, [5][6][7] ii) pairing with other OER-active counterparts for better activity, [8][9][10] iii) doping with heteroatoms (e.g., Fe, V, W, and Ce) to tailor the electronic structure and surface adsorption behaviors, [11][12][13][14][15][16][17] and iv) creating defective surfaces or interfaces. [18][19][20] Despite that significant efforts in regulating morphologies and/or structures have been undertaken, new 2D heterostructures provide another exciting opportunity for extending the application of 2D materials in energy conversionand storage devices, due to their flexibility in electronic structure modulations and surface chemistry regulations. Herein, by coupling liquid-exfoliated and mildly oxidized black phosphorus nanosheets (BP-NSs) with wet-chemically synthesized 2D nickel Ni(OH) 2 nanosheets (NH-NSs), 2D/2D heterostructured nanosheets (BNHNSs) are rationally constructed with a favorable transition of electron structure and desired intermediate adsorptions for alkaline oxygen evolution reaction (OER) catalysis. When used as an OER catalyst, to reach a current density of 10 mA cm −2 , the overpotential of 2D/2D BNHNSs is only 297 mV, corresponding to a considerable decrease of 22% and 34% compared with the individual 2D NH-NSs and 2D BP-NSs, respectively. The structural tracking at the initial reconstruction stage via time-dependent Raman spectra confirms that the phosphorus oxidization into the P-OH and the phase transformation into oxyhydroxide (NiOOH) significantly promote the electron transfer and electrocatalytic efficiency and thus endow the 2D/2D BNHNSs with much enhanced OER catalytic activity. This work offers new insights on the electron structure modulation of 2D-based heterostructures and opens new avenues for regulating the adsorption of emerging phosphorene-based materials for electrocatalysis.

High‐Entropy Catalyst—A Novel Platform for Electrochemical Water Splitting

“…[90] Last, but certainly not least, is the charge density difference, which helps understand the spatial distribution of electron density in the electrocatalyst structure. [91] Figure 3h is available for demonstrating the charge transfer due to the apparent electron depletion of Fe sites for the H 2 O adsorption, which was beneficial to the HER activity.…”

Heterostructure Engineering of 2D Superlattice Materials for Electrocatalysis

“…[221] In fact, most of the OER electrocatalysts are working as precatalysts, such as 2D transition metal materials, including transitional metal oxides/hydroxides/phosphide/carbides/nitrides, TMDs, etc. [73,222,223] The variations of surface structures and compositions could also happen in 2D superlattices, which should be operando monitored during the OER catalysis. The mechanical understanding on the transition states of OER catalysts may help the design of real phase and structure of 2D superlattices toward OER.…”

Hydrogen Production Technology Promotes the Analysis and Prospect of the Hydrogen Fuel Cell Vehicles Development under the Background of Carbon Peak and Carbon Neutrality in China

“…Ni-based metals are widely used as alkaline water electrolysis catalysts due to their high electrical conductivity, low cost, abundant sources, and high catalytic activity. − However, the practical industrial applications of nickel-based catalysts are limited by high energy consumption and high potential. In 2021, Luo et al prepared a high-performance nickel-based catalyst (h-NiMoFe) with three-dimensional porous morphology under high current conditions through hydrothermal reaction and high-temperature thermal reduction.…”