Soft Template‐Based Synthesis of Mesoporous Phosphorus‐ and Boron‐Codoped NiFe‐Based Alloys for Efficient Oxygen Evolution Reaction

Abstract

Controlling the morphology, composition, and crystalline phase of mesoporous nonnoble metal catalysts is essential for improving their performance. Herein, well‐defined P‐ and B‐codoped NiFe alloy mesoporous nanospheres (NiFeB‐P MNs) with an adjustable Ni/Fe ratio and large mesopores (11 nm) are synthesized via soft‐template‐based chemical reduction and a subsequent phosphine‐vapor‐based phosphidation process. Earth‐abundant NiFe‐based materials are considered promising electrocatalysts for the oxygen evolution reaction (OER) because of their low cost and high intrinsic catalytic activity. The resulting NiFeB‐P MNs exhibit a low OER overpotential of 252 mV at 10 mA cm−2, which is significantly smaller than that of B‐doped NiFe MNs (274 mV) and commercial RuO2 (269 mV) in alkaline electrolytes. Thus, this work highlights the practicality of designing mesoporous nonnoble metal structures and the importance of incorporating P in metallic‐B‐based alloys to modify their electronic structure for enhancing their intrinsic activity.

Ceria-Promoted Reconstruction of Ni-Based Electrocatalysts toward Efficient Oxygen Evolution

“…The consistent improvement was visible on CeO 2 -Ni 2 P/NF and CeO 2 -NiO/NF. Accordingly, Tafel analysis (Figure S15b,d,f) identified the lower slopes of CeO 2 -NiX/NF as compared with NiX/NF, indicating a fast increase of O 2 evolution rate with applied overpotential. , Moreover, C dl being proportional to the electrochemical surface area was evaluated (Figures S16 and S17), in which the higher C dl values of CeO 2 -decorated samples suggested the extended solid–liquid interfaces for OER on hierarchical CeO 2 -NiX nanostructures. , In addition, the EIS results confirmed the lower charge-transfer resistance ( R ct ) on CeO 2 -NiX/NF (Figure S18), in comparison with NiX/NF, associated with the accelerated electrode kinetics.…”

“…36,37 Moreover, C dl being proportional to the electrochemical surface area was evaluated (Figures S16 and S17), in which the higher C dl values of CeO 2 -decorated samples suggested the extended solid−liquid interfaces for OER on hierarchical CeO 2 -NiX nanostructures. 38,39 In addition, the EIS results confirmed the lower charge-transfer resistance (R ct ) on CeO 2 -NiX/NF (Figure S18), in compar-ison with NiX/NF, associated with the accelerated electrode kinetics.…”

Porous Nanoarchitectures of Nonprecious Metal Borides: From Controlled Synthesis to Heterogeneous Catalyst Applications

“…Several representative strategies, including lyotropic liquid crystals (LLCs), self-assembly of cationic surfactants, self-assembly of block copolymers, aggregation of nanoblocks, metal–organic framework (MOF)-derived pores, and heterostructure engineering, for preparing porous TMBs are presented in Figure . Different methods are favorable for fabricating different types of porous morphologies, such as two-dimensional (2D) hexagonal mesopores, worm-like mesopores, well-defined open mesopores, aggregated pores, MOF-derived pores, and hybridized pores, among others ,− (Table ).…”

“…63 Most recently, we successfully prepared mesoporous NiFeB with well-defined mesopores by strictly controlling the reduction conditions. 80 For instance, increasing reaction temperature (40 °C) and using an inert gas (Ar) throughout the restoration process were essential. Nevertheless, the atomic content of Fe in NiFeB was still limited to less than 10 at.…”

“…42 Recently, we highlighted the importance of further incorporating P to enhance the OER performance of mesoporous NiFeBbased alloy. 80 Addition of P in NiFeB provided an efficient technique for further tuning the electronic structures of active sites and enhancing the electrical conductivity, yielding a substantial increase in intrinsic activity. The mesoporous network Co−B−P also showed highly effective HER electrochemical performance in alkaline solution due to the synergistic effects of metal phosphide and boride.…”