Xin Wang,Yiyang Bi,Chengqian Wang,Ke Li,Yu Zhang,Qun Liu
In this research, we report a simple and cost-effective method for the preparation of two-dimensional (2D) Ni 2 P-Ni(PO 3 ) 2 derived from metal-organic frameworks (MOFs) via a one-step thermal phosphorization strategy. The resulting material is employed to significantly enhance the photocatalytic hydrogen evolution performance of zero-dimensional (0D) CdS nanoparticles. Through an ultrasonic-assisted strategy, the CdS nanoparticles are uniformly dispersed on the surface of Ni 2 P-Ni(PO 3 ) 2 , leading to the successful fabrication of a Ni 2 P-Ni(PO 3 ) 2 /CdS composite with substantially enhanced photocatalytic performance. Under visible light irradiation (λ ≥ 420 nm) using Na 2 S-Na 2 SO 3 as sacrificial agents, the 3 wt% Ni 2 P-Ni(PO 3 ) 2 /CdS composite demonstrated a remarkable photocatalytic hydrogen evolution rate of 2235 µmol g −1 h −1 , which is approximately 7.5 times higher than that of pristine CdS (297 µmol g −1 h −1 ). Over a 20 h cycling experiment, the composite catalyst demonstrated remarkable stability, maintaining around 78 % of its initial hydrogen generation efficiency. The enhanced performance of the composite is ascribed to the role of Ni 2 P-Ni(PO 3 ) 2 in facilitating the separation of photoinduced charge carriers from CdS and improving electrical conductivity. A possible electron-hole transfer mechanism is proposed based on the experimental findings. This work is expected to be helpful in fabricating efficient CdS photocatalysts.
The design and synthesis of efficient, inexpensive, and long-term stable heterostructured electrocatalysts with high-density dislocations for hydrogen evolution reaction in alkaline media and seawater are still a great challenge. An amorphous/crystalline/amorphous sandwiched structure with abundant dislocations were synthesized through thermal phosphidation strategies. The dislocations play an important role in the hydrogen evolution reactions. Copious dislocation defects, combined with cracks, and the synergistic interfacial effect between crystalline phase and amorphous phase regulate the electronic structure of electrocatalyst, provide more active sites, and thus endow the electrocatalysts with excellent catalytic activity under alkaline water and seawater. The overpotentials of P–NiMoO4 at 10 mA/cm2 in 1 M KOH aqueous solution and seawater are 45 and 75 mV, respectively. Additionally, the P–NiMoO4 electrocatalyst exhibits long-term stability over 100 h. This study provides a simple approach for synthesizing amorphous/crystalline/amorphous sandwiched non-noble-metal electrocatalysts with abundant dislocations for hydrogen evolution reaction.
Aiming to design and prepare non-noble metal electrocatalysts for hydrogen production at high current density (HCD), NiCoP@FeNi LDH hierarchical nanosheets were deposited on nickel foam progressively using a hydrothermal-phosphorization-electrodeposition process. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), NiCoP@FeNi LDH/NF requires only 195 and 230 mV overpotentials to reach 1000 mA cm −2 , respectively. For overall water splitting, only 1.70 V is required at 1000 mA cm −2 . This is the largest value for non-noble metal-based electrocatalysts reported so far at HCD. The hierarchical structure exhibits good electron transport capability and the porous-macroporous structure enhances the gas release rate, resulting in enhanced hydrogen production at HCD. Especially, the synergistic effect of NiCoP and FeNi LDH contributes to the adsorption-desorption equilibrium of intermediate radicals during the reaction process and ultimately enhances the catalytic activity. This work provides useful direction for industrial-scale hydrogen production applications at HCD.
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