Nanoengineering of P, Se co-doped hollow microspheres induced charge redistribution with P-Se-M bond as...

Exploring a multifunctional catalyst that possesses excellent catalytic activities for the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) is essential for the storage and conversion of renewable energy. Here, a newfangled trifunctional P decorated and nitrogen-doped carbon (NC) coated selenide material (CoSe₂@FeSe₂/P_2.5/NC) was fabricated by in-situ heteroatom doping and selenylation strategy. CoFe₂O₄ particles were firstly fabricated by hydrothermal, next blended with 2-methylimidazole and Zn(NO₃)₂·6H₂O, followed by two-step pyrolysis and phosphating to form the CoSe₂@FeSe₂/P_2.5/NC catalyst. The hollow structure possesses a large void size and a specific surface area was constructed by encapsulating CoFe₂O₄ particles with a zeolitic imidazolate framework-8 (ZIF-8) derived NC cube layer. The bonding of Se with the highly electronegative P and metal causes the charge to redistribute through the P-Se-M (M= Co, Fe) structure, thereby weakening the adsorption energy of P-containing substances. Its unique hollow structure and high conductivity made the screened CoSe₂@FeSe₂/P_2.5/NC have superior ORR properties with the onset potential (E₀) of 0.96 V and half-wave potential (E_1/2) of 0.85 V. In alkaline electrolytes, the lower overpotential of 289 mV (10 mA/cm²) and the 526 mV (100 mA/cm²) also exhibited distinguished OER and HER catalytic activities. Besides, the density functional theory (DFT) results concurrently demonstrated that CoSe₂@FeSe₂/P_2.5/NC optimized the adsorption of O*/OOH* (adsorbed O/OOH atoms) intermediates for OER and H* (adsorbed H atoms) intermediates for HER. The excellent trifunctional catalytic effect was put down to the charges redistribution effect at the interface of various components constructed by the Se element and the effect of the P element on enhancing conductivity. This study reveals that heteroatom-doped nanoengineering is an effective technique for optimizing electronic structures and boosting the electrocatalytic performance of catalysts.