Manganese‐Doped Bimetallic (Co,Ni)2P Integrated CoP in N,S Co−Doped Carbon: Unveiling a Compatible Hybrid Electrocatalyst for Overall Water Splitting

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-05, Vol.20 (18), p.e2307241-n/a
• Main Authors: Kandel, Mani Ram, Pan, Uday Narayan, Dhakal, Purna Prasad, Ghising, Ram Babu, Sidra, Saleem, Kim, Do Hwan, Kim, Nam Hoon, Lee, Joong Hee
• Format: Article
• Language: English
• Subjects: Bimetals; Carbon; Catalysts; Chemical vapor deposition; Cobalt; Density functional theory; Electrocatalysts; Electrodes; HER; heterointerface; Heterostructures; Hybrid structures; Hydrogen evolution reactions; Manganese; Metal foams; metal–organic frameworks; Nickel; Nitrogen; OER; Oxygen evolution reactions; Oxygen production; phosphidation; Phosphides; Synergistic effect; Water splitting
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202307241

Rational design of highly efficient noble‐metal‐unbound electrodes for hydrogen and oxygen production at increased current density is crucial for robust water‐splitting. A facile hydrothermal and room‐temperature aging method is presented, followed by chemical vapor deposition (CVD), to create a self‐sacrificed hybrid heterostructure electrocatalyst. This hybrid material, (Mn−(Co,Ni)2P/CoP/(N,S)−C), comprises manganese‐doped cobalt nickel phosphide (Mn−(Co,Ni)2P) nanofeathers and cobalt phosphide (CoP) nanocubes embedded in a nitrogen and sulfur co‐doped carbon matrix (N,S)−C on nickel foam. The catalyst exhibits excellent performance in both the hydrogen evolution reaction (HER; η10 = 61 mV) and oxygen evolution reaction (OER; η10 = 213 mV) due to abundant active sites, high porosity, and enhanced hetero‐interface interaction between Mn−(Co2P−Ni2P) CoP, and (N,S)−C supported by significant synergistic effects observed among different phases through density functional theory (DFT) calculations. Impressively, (Mn−(Co,Ni)2P/CoP/(N,S)−C (+,−) shows an extra low cell voltage of 1.49 V@10 mA cm−2. Moreover, the catalyst exhibits remarkable stability at 100 and 300 mA cm−2 when operating as a single stack cell electrolyzer. The superior electrochemical activity is attributed to the enhanced electrode–electrolyte interface among the multiple phases of the hybrid structure. The hybrid electrocatalyst (Mn−(Co,Ni)2P/CoP/(N,S)−C) develops through a hydrothermal and room‐temperature aging method followed by chemical vapor deposition, exhibits outstanding performance in hydrogen and oxygen evolution reactions. The catalyst's effectiveness is attributed to abundant active sites, high porosity, and improved hetero‐interface interaction among different phases, leading to a low cell voltage of 1.49 V@10 mA cm−2 and notable stability.