In situ phosphoselenization induced heterointerface engineering endow NiSe2/Ni2P/FeSe2 hollow nanocages with efficient water oxidation electrocatalysis performance

In Situ Electrodeposition of Ultralow Pt into NiFe-Metal-Organic Framework/Nickel Foam Nanosheet Arrays as a Bifunctional Catalyst for Overall Water Splitting

Exploring highly effective bifunctional electrocatalysts with surface structural advantages and synergistic optimization effects among multimetals is greatly important for overall water splitting. Herein, we successfully synthesized Pt-loaded NiFe-metal-organic framework nanosheet arrays grown on nickel foam (Pt-NiFe-MOF/NF) via a facile hydrothermal-electrodeposition process. Benefiting from large exposed specific surface, optimal electrical conductivity and efficient metal-support interaction endow Pt-NiFe-MOF/NF with highly catalytic performance, exhibiting small overpotential of 261 mV toward oxygen evolution reaction and 125 mV toward hydrogen evolution reaction at a current density of 100 mA cm-2 in alkaline medium. More significantly, the assembled water electrolyzer comprising the Pt-NiFe-MOF/NF//Pt-NiFe-MOF/NF couple demands a low cell voltage of 1.45 V to reach 10 mA cm-2. This work renders a viable approach to design dual-functional electrocatalysts with exceptional electrocatalytic activity and stability at high current density, showing the great prospect of water electrolysis for commercial application.

Defect engineering induces Mo-regulated Co9Se8/FeNiSe heterostructures with selenium vacancy for enhanced electrocatalytic overall water splitting in alkaline

The pursuit of cost-effective catalysts for electrocatalytic overall water splitting continues to present a significant challenge in the field. A molybdenum (Mo)-regulated Co9Se8/FeNiSe self-supporting electrode material with rich vacancy defects has been prepared by hydrothermal reaction. Doping of Mo atoms not only can form rich selenium vacancy defects to enrich the inherent activity of the catalyst, but also expose more active sites. The intrinsic electronic architecture of the interface catalysis is regulated and optimized through the introduction of heteroatom Mo, resulting in the exceptional catalytic activities of the Mo-Co9Se8/FeNiSe heterostructure. Additionally, the Faraday efficiency of hydrogen (H2) and oxygen (O2) production approaches 100 %. The voltage required for the water-splitting system is only 1.58 V (10 mA cm-2), and 100 h stability test at 100 mA cm-2 demonstrates no decay. This work presents a new perspective for the reasonable design and synthesis of non-precious metal selenide-based bifunctional electrocatalysts.

Polyethylenimine-Ethylenediamine-Induced Pd Metallene toward Alkaline Oxygen Reduction

Designing two-dimensional (2D) materials functionalized with organic molecules is an effective tactic to enhance catalytic performances for the oxygen reduction reaction (ORR). Herein, we synthesize Pd metallene with in situ modification of polyethylenimine-ethylenediamine (Pd@PEI-EDA metallene), in which PEI-EDA serves as both the structure-directing agent and modifier. Pd@PEI-EDA metallene has ample active sites and tuneable electronic structures due to ultrathin nanosheets with abundant wrinkles and interfacial structure. In contrast with commercial Pd/C and Pt/C, Pd@PEI-EDA metallene displays preferable catalytic ORR performance under alkaline conditions. This work offers an in situ interface engineering tactic for the preparation of 2D polymer-metal electrocatalysts to boost the ORR performance.