Xiaohui Zhong,Zuqi Zhong,Shujie Liang,Gongchang Zeng,Shuang Cheng,Hong Deng,Zhang Lin
The electrochemical CO2 reduction reaction (CO2RR) to HCOOH offers a promising strategy for a carbon-neutral cycle. Sn-Based materials have been demonstrated as applicable in extensive studies of CO2RR to HCOOH, but great challenges still remain, including the weak CO2 adsorption and narrow potential window as well as low stability. Herein, we developed ultrasmall Sn nanoparticles inlaid on N/P-doped carbon (Sn@NPC) composites by an upcycling design using Sn electroplating sludge. The obtained Sn@NPC electrode exhibited a higher Faradaic efficiency of 87.93% for HCOOH at 1.05 V vs. RHE and an FE over 80% within a 500 mV broad potential window. Moreover, the Sn@NPC electrode achieved excellent long-term stability up to 105 h, which was superior to that of most Sn-based catalysts in similar systems. Density functional theory calculations demonstrated that Sn@NPC could enhance CO2 adsorption, which led to stronger *OCHO adsorption, weaker *HCOOH adsorption and faster electron/mass transport. This work may provide a promising lead for recycling metal from electroplating sludge and for the design of efficient and stable catalysts for the CO2RR.
Kewei Shu,Cunguo Yang,Huizhu Niu,Xiaorui Fuyan,Shuqi Yang,Haihua Wang
GeP 3 is a promising anode material for sodium ion battery due to better conductivity, relatively high theoretical capacity and improved mechanical endurance compared to phosphorus and other phosphides. However unsatisfied rate capability and cycling stability is still an annoying issue that hinders the application of GeP 3 . Here, GeP 3 was hybridized with P doped carbon (PPC) derived from low-cost coal tar pitch to prepare composite electrode. Through ball-milling process, the GeP 3 and PPC was homogenously mixed and form fused, secondary particles as confirmed by electron microscope. The formation of P-C and P-O-C bond between GeP 3 and carbon matrix was evidenced by XPS, and prompted by P doping level and O content in PPC. The electrochemical performance of the composite electrodes was evaluated, demonstrated much enhanced properties compared to bare GeP 3 and also GeP 3 /carbon black electrode. High reversible capacity of 781 mAh/g was achieved by GeP 3 /PPC-950 at 0.05 A/g. At higher current density of 2 A/g, the capacity can maintain at 360 mAh/g, 46% of the value that obtained at 0.05 A/g. The correlation between the structure of carbon and battery performance was discussed. The improvement in battery performance can be attributed to suppressed volume expansion and good conductive network of the GeP 3 /PPC composite, which affected by P doping level and O content of PPC.
Transition-metal phosphides have been identified as effective materials for improving electrocatalytic hydrogen evolution. In this study, Ni2P, Co2P, and NiCoP yolk–shell structures were embedded in N- and P-doped carbon nanofibers (NPNFs) by controlling the heat-treatment procedure of the fiber precursors. The hydrogen evolution reaction (HER) activity of the samples was tested. The formation process of phosphides introduced a large number of surface defects that act as active sites to improve H2 evolution. NPNF embedding composite NiCoP particles exhibited better performance compared with Ni2P–NPNFs and Co2P–NPNF samples in acidic conditions. In the case of a molar ratio Ni : Co : P of 1 : 1 : 1, NiCoP-decorated NPNFs revealed the best HER performance, which is ascribed to the loading of NiCoP composite particles, which greatly increased the specific surface area. NiCoP–NPNFs exhibited overpotentials of 183 and 280 mV at current densities of 1 mA cm−2 and 10 mA cm−2, respectively, with a Tafel slope of 94.5 mV dec−1.
Precious metal phosphides have attracted considerable research interest for electrocatalysis in recent years, but it remains an open question how to design such electrocatalysts to facilitate the gas-evolving water electrolysis with high activity and durability at low metal loading. In this work, rhodium phosphide nanoparticles are attached on a nitrogen/phosphorus-doped carbon cloth matrix (Rh2P-N/P-CC) with an ultralow Rh loading of 39.2 μg cm–2 to be used as an excellent bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). By rationally integrating the merits of its two components, as-reported Rh2P-N/P-CC exhibits impressive HER catalytic performance, outperforming benchmark Pt/C catalysts at only 7.85% equivalent of Pt; meanwhile, Rh2P-N/P-CC largely surpasses the RuO2 catalyst during OER catalysis in alkaline media. As a bifunctional electrocatalyst, Rh2P-N/P-CC catalyzes stable electrochemical water splitting of 200 mA cm–1 under 1.7 V. This work reports a feasible strategy to integrate three-dimensional electrodes for high performance water electrolysis.
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