The advancement of direct seawater electrolysis is a significant step towards sustainable hydrogen production,addressing the critical need for renewable energy sources and efficient resource utilization.However,direct seawater electrolysis has to face several challenges posed by the corrosiveness of highly concentrated chloride and the competitive chlorine evolution reaction(ClER).To overcome these issues,we designed a novel NiP_(2)@CoP electrocatalyst on a porous titanium microfiltration(Ti MF)membrane.The obtained bifunctional NiP_(2)@CoP catalyst outperforms the Pt/C and IrO_(2),as evidenced by its low overpotentials of 192 and 425 mV at a current density of 500 mA·cm^(-2) for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in alkaline seawater(1 M KOH+0.5 M NaCl),respectively.Especially,only 231 and 569 mV overpotentials are required at the current density of 1500 mA·cm^(-2) towards HER and OER in alkaline seawater,respectively.More importantly,no ClER was observed,demonstrating its excellent selectivity to OER.The selection of porous Ti MF membrane as an electrode substrate further enhances the performance by providing a robust structure that promotes the fast generation and release of gas bubbles.Our promising outcomes obtained with NiP_(2)@CoP catalysts on Ti MF support,therefore,pave the way for the commercial viability of direct seawater electrolysis technologies at industrial-level current densities.
The development of cost-effective and durable hydrogen evolution reaction(HER)electrocatalysts plays a vital role in dealing with the issues related to carbon dioxide emission.Cobalt phosphide-based nanomaterials are evaluated as promising advocates for HER due to high catalytic activities,good stability,and rich defect.This review commences with an exploration of the synthetic pathways of CoP,including solid-phase,solution-phase along with electrochemical methods.Besides,the mechanism of hydrogen formation is expressed thoroughly,after which various integrated strategies of morphology engineering with doping,assisted highly conductive materials,and construction of heterostructure were introduced for HER.Ultimately,burdensome tasks and possible guidance for the advancement of CoP-based nanomaterials were discussed for hydrogen production.
Electrocatalytic water splitting is the most directly available route to generate renewable and sustainable hydrogen.Here,we report the design of a composite material in which arrays of square pillar-like NiMoO4nanorods coated with N,P-doped carbon layers are uniformly contained in numerous nested nanoparticle structures.The catalysts have superior catalytic activity,requiring only 59 mV and 187 mV for HER and OER to attain a current density of 10 mA/cm^(2),respectively.The assembled two-electrode electrolytic cell required a voltage of 1.48 V to reach 10 mA/cm^(2),along with excellent long-term stability.Theoretical calculations reveal that electrons aggregate and redistribute at the heterogeneous interface,with the d-band centers of the Ni and Fe atoms being positively shifted compared to the Fermi level,effectively optimizing the adsorption of intermediates and reducing the Gibbs free energy,thus accelerating the catalytic process.Meanwhile,an integrated solar-driven water-splitting system demonstrated a high and stable solar-to-hydrogen efficiency of 18.20%.This work provides new possibilities for developing non-precious metal-based bifunctional electrocatalysts for large-scale water splitting applications.
The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a challenge.NMPs have attracted increasing attentions,but the preparation process often needs toxic regents or dangerous reaction conditions.Herein,we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked complexes.The obtained Ru_(2) P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm^(2) and ultralow Tafel slope of 33 mV dec^(-1) in 1.0 mol L?1 KOH,even better than that of commercial Pt/C.In addition,Ru 2 P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L^(-1) H_(2)SO_(4) and 1.0 mol L^(-1) PBS,respectively.The superior activity can be attributed to the ultrafine dispersion of Ru 2 P nanoparticles for more accessible sites,more defects formed for abundant active sites,the two-dimensional plane structure for accelerated electron transfer and mass transport,as well as the regulation of electron distribution of the catalyst.Moreover,the synthetic method can also be applied to prepare other metal-rich noble metal phosphides(Pd_(3)P-NPG and Rh_(2)P-NPG),which also exhibits high activity for HER.This work provides an effective strategy for designing NMP-based electrocatalysts.
Jingwen MaXiang LiGuangyu LeiJun WangJuan WangJian LiuMing KeYang LiChunwen Sun
The electronic modulation characteristics of efficient metal phosphide electrocatalysts can be utilized to tune the performance of oxygen evolution reaction(OER).However,improving the overall water splitting performance remains a challenging task.By building metal organic framework(MOF)on MOF heterostructures,an efficient strategy for controlling the electrical structure of MOFs was presented in this study.ZIF-67 was in-situ synthesized on MIL-88(Fe)using a two-step self-assembly method,followed by low-temperature phosphorization to ultimately synthesize FeP-CoP_(3)bimetallic phosphides.By combining atomic orbital theory and theoretical calculations(density functional theory),the results reveal the successful modulation of electronic orbitals in FeP-CoP_(3)bimetallic phosphides,which are synthesized from MOF on MOF structure.The synergistic impact of the metal center Co species and the phase conjugation of both kinds of MOFs are responsible for this regulatory phenomenon.Therefore,the catalyst demonstrates excellent properties,demonstrating HER 81 mV(η10)in a 1.0 mol L^(−1)KOH solution and OER 239 mV(η50)low overpotentials.The FeP-CoP_(3)linked dual electrode alkaline batteries,which are bifunctional electrocatalysts,have a good electrocatalytic ability and may last for 50 h.They require just 1.49 V(η50)for total water breakdown.Through this technique,the electrical structure of electrocatalysts may be altered to increase catalytic activity.
Bohan AnWeilong LiuJipeng DongNing LiYangqin GaoLei Ge
The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy.Herein,we present a multistep strategy for the synthesis of a Ti_(3)C_(2) MXene ribbon/NiFePx@graphitic N-doped carbon(NC)heterostructure that enables the formation of three-dimensional(3D)Ti_(3)C_(2) MXene ribbon networks and bimetallic phosphide nanoarrays.With the assistance of HF etching and KOH shearing,the MXene sheets were successfully transformed into 3D MXene networks with interlaced MXene ribbons.Notably,a hydrothermal method,ion exchange route,and phosphorization process were used to anchor NiFeP_(x)@NC nanocubes derived from Ni(OH)_(2)/NiFe-based Prussian blue(NiFe-PB)onto the MXene ribbon network.The resulting MXene ribbon/NiFeP_(x)@NC heterostructure demonstrated enhanced oxygen evolution reaction(OER)activity,characterized by a low overpotential(164 mV at a current density of 10 mA cm^(-2))and a low Tafel slope(45 mV dec^(-1)).At the same time,the MXene ribbons/NiFeP_(x)@NC heterostructure exhibited outstanding long-term stability,with a 12 mV potential decay after 5000 cyclic voltammetry(CV)cycles.This study provides a robust pathway for the design of efficient MXene-based heterostructured electrocatalysts for water splitting.
One key step for advancing the widespread practical application of rechargeable metal-air batteries and water electrolysis fundamentally relies on the development of cost-effective multifunctional electrocata-lysts toward oxygen and hydrogen-involving reactions.The present work initiates a tofu-derived one-pot strategy for green,facile,and mass production of highly active and stable catalyst toward oxygen reduc-tion/evolution and hydrogen evolution reactions,through the preparation of Fe/Co cross-linked tofu gel and the subsequent pyrolysis.Despite the free use of additional N/P precursors or pore-forming agents,the as-prepared materials comprise highly dispersive FeCo-rich phosphides nanoparticles and porous N,P co-doped carbon network inherited from the tofu skeleton.The resultant catalysts exhibit remarkably enhanced trifunctional activities as compared to the Fe_(2)P and Co_(2)P counterparts,along with better long-term stabilities than the benchmark RuO_(2)and Pt/C catalysts.Accordingly,the as-assembled Zn-air battery delivers a large power density(174 mW cm^(-2))with excellent cycle stability(the gap of charge/discharge voltage@10 mA cm^(-2)increases by 0.01 V after 720 h of operation,vs.0.16 V of Pt/C-RuO_(2)based battery after 378 h).Furthermore,the as-constructed alkaline electrolyzer just requires a small voltage of 1.55 V@10 mA cm^(-2),which outperforms nearly all of those of biomass-derived electrocatalysts ever reported,and that of noble metal catalysts-based electrolyzers(1.72 V@10 mA cm^(-2)for Pt/C-RuO_(2)),underscoring their bright future toward commercial applications in green energy conversion devices.
Bo WangQiao LiuAo YuanQing ShiLan JiangWeiyou YangTao YangXinmei Hou
The coupling of energy-saving small molecule conversion reactions and hydrogen evolution reaction(HER)in seawater electrolytes can reduce the energy consumption of seawater electrolysis and mitigate chlorine corrosion issues.However,the fabrication of efficient multifunctional catalysts for this promising technology is of great challenge.Herein,a heterostructured catalyst comprising CoP and Ni_(2)P on nickel foam(CoP/Ni_(2)P@NF)is reported for hydrazine oxidation(HzOR)-assisted alkaline seawater splitting.The coupling of CoP and Ni_(2)P optimizes the electronic structure of the active sites and endows excellent electrocatalytic performance for HzOR and HER.Impressively,the two-electrode HzOR-assisted alkaline seawater splitting(OHzS)cell based on the CoP/Ni_(2)P@NF required only 0.108 V to deliver 100 mA·cm^(−2),much lower than 1.695 V for alkaline seawater electrolysis cells.Moreover,the OHzS cell exhibits satisfactory stability over 48 h at a high current density of 500 mA·cm^(−2).Furthermore,the CoP/Ni_(2)P@NF heterostructured catalyst also efficiently catalyzed glucose oxidation,methanol oxidation,and urea oxidation in alkaline seawater electrolytes.This work paves a path for high-performance heterostructured catalyst preparation for energy-saving seawater electrolysis for H_(2) production.
