Muhammad Asim,Alibek Kurbanov,Bushra Maryam,Muhammad Ajmal,Chenxiang Shi,Lun Pan,Ji-Jun Zou
Incorporating g-C 3 N 4 with transition metal phosphides is emerging as a low-cost and robust co-catalyst for hydrogen evolution . The ammonia borane hydrolysis is an efficient method to release H 2 at ambient conditions in the presence of a catalyst. An efficient and cheap catalyst is needed for practical application to achieve this benchmark. For this purpose, a catalyst Ni 2 P/C 3 N 4 is synthesized by hydrothermal method and low-temperature phosphidation. The optimization reveals that the Ni 2 P/C 3 N 4 with 6.5% Ni contents shows the best performance for H 2 release. Furthermore, 2% Pt nanoparticles loading over Ni 2 P/C 3 N 4 boosts the charge transfer and improves activity 5.7-fold compared to Ni 2 P/C 3 N 4 , and the Pt-loaded catalyst is depicted as Pt@Ni 2 P/C 3 N 4 . The reaction kinetics reveals that the hydrogen evolution rate accelerates by increasing the amount of Pt@Ni 2 P/C 3 N 4 and AB concentration, and the loading of Pt nanoparticles loaded over Ni 2 P/C 3 N 4 reduces the activation energy significantly. Moreover, the ionic interaction between Pt and Ni 2 P/C 3 N 4 generates Ptᵟ + and (Ni 2 P/C 3 N 4 )ᵟ − active sites which facilitates B–H cleavage and O–H bonds of ammonia borane and water, respectively. Incorporating transition metals phosphide and noble metals supported over g-C 3 N 4 paves the pathway toward the efficient H 2 evolution from ammonia borane, bringing cost-effective modifications to synthesize constructive catalysts.
Lithium-sulfur (Li-S) batteries, renowned for their exceptional theoretical energy density, are positioned as a leading candidate for future energy storage systems, offering a potential pathway to overcome the energy density limitations of conventional lithium-ion batteries. Nevertheless, the notorious lithium polysulfides (LiPSs) shuttle effect and sluggish redox kinetics hinder their practical application. To resolve these challenges, we report a novel NiO-Ni 2 P/C 3 N 4 heterostructure synthesized via an in-situ phosphation process. Herein, we present an in situ phosphorylation strategy for the construction of NiO-Ni 2 P heterojunctions anchored on a conductive C 3 N 4 substrate (NiO-Ni 2 P/C 3 N 4 ) for further integration into commercial polypropylene (PP) separator (denoted as NiO-Ni 2 P/C 3 N 4 @PP). Mechanistic studies demonstrated that the NiO phase facilitated strong chemisorption of LiPSs, while the Ni 2 P component reduced the energy barrier for Li 2 S dissolution through optimised d-band electron transfer. Concurrently, the C 3 N 4 framework enhanced the interfacial charge transfer and significantly reduced the charge transfer resistance. Benefiting from the synergistic “adsorption-transformation-conduction” triple-function, the cells with the NiO-Ni 2 P/C 3 N 4 @PP separator exhibit remarkable cycling stability (over 300 cycles at 3C) and outstanding rate capability (82.5 % capacity retention after 200 cycles at 5C). This work provides atomic-level insights into the engineering of multi-step sulfur electrochemical heterostructures, providing a generic design paradigm for high-energy metal-sulfur batteries.
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