Atmospheric‐Temperature Chain Reaction towards Ultrathin Non‐Crystal‐Phase Construction for Highly Efficient Water Splitting

Abstract

Combining the self-sacrifice of a highly crystalline substance to design a multistep chain reaction towards ultrathin active-layer construction for high-performance water splitting with atmospheric-temperature conditions and an environmentally benign aqueous environment is extremely intriguing and full of challenges. Here, taking cobalt carbonate hydroxides (CCHs) as the initial crystalline material, we choose the Lewis acid metal salt of Fe(NO 3 ) 3 to induce an aqueous-phase chain reaction generating free CO 3 2À ions with subsequent instant FeCO 3 hydrolysis. The resultant ultrathin (~5 nm) amorphous Fe-based hydroxide layer on CCH results in considerable activity in catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), yielding 10/50 mA • cm À 2 at overpotentials of 230/266.5 mV for OER and 72.5/197.5 mV for HER. The catalysts can operate constantly in 1.0 M KOH over 48 and 45 h for the OER and HER, respectively. For bifunctional catalysis for alkaline electrolyzer assembly, a cell voltage as low as 1.53 V was necessary to yield 10 mA cm À 2 (1.7 V at 50 mA cm À 2 ). This work rationally builds high-efficiency electrochemical bifunctional water-splitting catalysts and offers a trial in establishing a controllable nanolevel ultrathin lattice disorder layer through an atmospheric-temperature chemical route.

Electrochemical In Situ Self-Healing of Porous Nanosheets Based on the Phase Reconstruction of Carbonate Hydroxide to Layered Double Hydroxides with Unsaturated Coordination Metal Sites for High-Performance Water Oxidation

“…43 Finally, a typical standard three-electrode configuration and an alkaline electrolyte were used to evaluate the changes in OER activity and stability of the catalyst before and after CV cycles. 44,45 To investigate the difference in structure and performance between the active phase of NF-LDH captured by the electrochemical process and the traditional NF-LDH directly synthesized, we first synthesized the NF-LDH nanosheets array (NF-LDH/F) by referring to the typical hydrothermal method, as reported. 38 The characteristic peaks displayed in XRD patterns and the signal peaks appearing in the Raman and FT-IR spectra of NF-LDH/F (Figure S17 in the Supporting Information) are completely consistent with those of NF-LDH, proving the successful synthesis of NF-LDH/F.…”

Amorphous Co-Mo-B Film: A High-Active Electrocatalyst for Hydrogen Generation in Alkaline Seawater

“…The growing global energy crisis and environmental problems caused by the massive consumption of traditional non-renewable resources drive humans to explore eco-friendly and renewable energy, and hydrogen (H 2 ) is a desirable alternative to fossil fuels on account of its high calorific value and pollution-free features [ 1 , 2 , 3 , 4 ]. Water electrolysis technology provides a facile and sustainable route for the massive generation of high-purity H 2 [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Nevertheless, large-scale water electrolysis would doubtlessly exacerbate the shortage of freshwater.…”

Crystalline-Dependent Discharge Process of Locally Enhanced Electrooxidation Activity on Ni2P

“…Hydrogen, a clean, renewable energy source with high energy density, can be prepared by electrochemical water splitting and thus serve as an alternative to fossil fuels. − The sluggish kinetics of the anode half-reaction, oxygen evolution reaction (OER), result in a large overpotential and thus become the bottleneck to the overall efficiency of water-splitting devices. − Electrocatalysts, as a useful tool to facilitate the process intensification of electrochemical reactions, possess a strong ability to reduce the reaction barrier and the eventual improvement of reaction kinetics. , Most research until now has focused on optimizing the as-prepared electrocatalysts with well-defined composites and nanostructures. − However, the electrocatalysts would undergo a reconstruction process under a complex strong alkaline chemical environment, offering a much unusual interface during the OER. , The fundamental understanding behind the correlation of the as-prepared electrocatalysts and the electrochemical process is essential for realizing current techniques for large-scale applications while still being challenging …”