与质子交换膜燃料电池相比,碱性交换膜燃料电池(AEMFC)能够同时在阳极和阴极使用非贵金属,从而显著降低燃料电池的成本.目前,在阴极氧还原反应(ORR)已经开发出可以媲美Pt/C的非贵金属催化剂,而阳极氢氧化反应(HOR)最有希望的非贵金属催...与质子交换膜燃料电池相比,碱性交换膜燃料电池(AEMFC)能够同时在阳极和阴极使用非贵金属,从而显著降低燃料电池的成本.目前,在阴极氧还原反应(ORR)已经开发出可以媲美Pt/C的非贵金属催化剂,而阳极氢氧化反应(HOR)最有希望的非贵金属催化剂仅限于镍基催化剂,且其催化性能却远落后于铂基电催化剂.因此,开发高效、稳定的碱性HOR镍基催化剂对于推动AEMFC的实际应用具有重要意义.本文通过对负载在XC-72上的无定型硼化镍(NiB/C)进行煅烧,得到了硼掺杂的镍(B-Ni/C).粉末X射线晶体衍射结果表明,煅烧后催化剂的晶体形式为fcc相的Ni.透射电子显微镜结果表明,催化剂呈分散的纳米颗粒状态,能量色散光谱图也证明了Ni、B元素均匀分布于C上.在0.1 mol/L KOH条件下进行HOR活性测试,B-Ni/C样品的比面积交换电流密度和在50 mV过电位下的比质量交换电流密度分别为0.035 mA cm_(Ni)^(–2)和27.95 mA mg_(Ni)^(–1),与未掺杂硼的镍碳(Ni/C)催化剂相比,其质量活性提高了10倍.在加速耐久性测试中,B-Ni/C催化剂在氩气中1000圈电位循环后仍具有一定的氢氧化活性,表明其具有较好的抗氧化稳定性.在含有万分之一浓度CO的H_(2)中进行长时间计时电流法测试结果表明,相比于Pt/C,NiB/C活性仅有轻微损失,表现出出色的抗CO能力.此外B-Ni/C在1 mol/L KOH条件下也具有较好的HER性能,仅需128 mV的过电位就可以达到10 mA cm^(‒2)的电流密度.实验和密度泛函理论计算表明,B掺杂后,B的p轨道和Ni的d轨道之间会形成d-p杂化,从而促进Ni表面对OH的吸附,同时优化了其表面的氢结合能,降低了水物种的形成能,有助于提高碱性条件下的HOR性能.综上,本文通过简单方法设计了一种杂原子掺杂的镍基催化剂,其表现出较好的氢氧化活性,为开发低成本、高效的非铂碱性HOR催化剂提供了新的视角.展开更多
The development of efficient and cost-effective electrocatalysts toward anodic oxygen evolution reaction(OER) is crucial for the commercial application of electrochemical water splitting.As the most promising electroc...The development of efficient and cost-effective electrocatalysts toward anodic oxygen evolution reaction(OER) is crucial for the commercial application of electrochemical water splitting.As the most promising electrocatalysts,the OER performances of nickel-iron-based materials can be further improved by introducing metalloid elements to modify their electron structures.Herein,we developed an efficient hybrid electrocatalyst with nickel-iron boride(NiFeB) as core and amorphous nickel-iron borate(NiFeBi)as shell(NiFeB@NiFeBi) via a simple aqueous reduction.The obtained NiFeB@NiFeBi exhibits a small overpotential of 237 mV at 10 mA/cm^2 and Tafel slope of 57.65 mV/dec in 1.0 mol/L KOH,outperforming most of the documented precious-metal-free based electrocatalysts.Benefiting from the in situ formed amorphous NiFeBi layer,it shows excellent stability toward the oxygen evolution reaction(OER).These findings might provide a new way to design advanced precious-metal-free electrocatalysts for OER and the application of electrochemical water splitting.展开更多
文摘与质子交换膜燃料电池相比,碱性交换膜燃料电池(AEMFC)能够同时在阳极和阴极使用非贵金属,从而显著降低燃料电池的成本.目前,在阴极氧还原反应(ORR)已经开发出可以媲美Pt/C的非贵金属催化剂,而阳极氢氧化反应(HOR)最有希望的非贵金属催化剂仅限于镍基催化剂,且其催化性能却远落后于铂基电催化剂.因此,开发高效、稳定的碱性HOR镍基催化剂对于推动AEMFC的实际应用具有重要意义.本文通过对负载在XC-72上的无定型硼化镍(NiB/C)进行煅烧,得到了硼掺杂的镍(B-Ni/C).粉末X射线晶体衍射结果表明,煅烧后催化剂的晶体形式为fcc相的Ni.透射电子显微镜结果表明,催化剂呈分散的纳米颗粒状态,能量色散光谱图也证明了Ni、B元素均匀分布于C上.在0.1 mol/L KOH条件下进行HOR活性测试,B-Ni/C样品的比面积交换电流密度和在50 mV过电位下的比质量交换电流密度分别为0.035 mA cm_(Ni)^(–2)和27.95 mA mg_(Ni)^(–1),与未掺杂硼的镍碳(Ni/C)催化剂相比,其质量活性提高了10倍.在加速耐久性测试中,B-Ni/C催化剂在氩气中1000圈电位循环后仍具有一定的氢氧化活性,表明其具有较好的抗氧化稳定性.在含有万分之一浓度CO的H_(2)中进行长时间计时电流法测试结果表明,相比于Pt/C,NiB/C活性仅有轻微损失,表现出出色的抗CO能力.此外B-Ni/C在1 mol/L KOH条件下也具有较好的HER性能,仅需128 mV的过电位就可以达到10 mA cm^(‒2)的电流密度.实验和密度泛函理论计算表明,B掺杂后,B的p轨道和Ni的d轨道之间会形成d-p杂化,从而促进Ni表面对OH的吸附,同时优化了其表面的氢结合能,降低了水物种的形成能,有助于提高碱性条件下的HOR性能.综上,本文通过简单方法设计了一种杂原子掺杂的镍基催化剂,其表现出较好的氢氧化活性,为开发低成本、高效的非铂碱性HOR催化剂提供了新的视角.
基金financially supported by the National Natural Science Foundation of China(No.21972107)the National Natural Science Foundation of Jiangsu Province(No.BK20191186)the Large-Scale Instrument and Equipment Sharing Foundation of Wuhan University。
文摘The development of efficient and cost-effective electrocatalysts toward anodic oxygen evolution reaction(OER) is crucial for the commercial application of electrochemical water splitting.As the most promising electrocatalysts,the OER performances of nickel-iron-based materials can be further improved by introducing metalloid elements to modify their electron structures.Herein,we developed an efficient hybrid electrocatalyst with nickel-iron boride(NiFeB) as core and amorphous nickel-iron borate(NiFeBi)as shell(NiFeB@NiFeBi) via a simple aqueous reduction.The obtained NiFeB@NiFeBi exhibits a small overpotential of 237 mV at 10 mA/cm^2 and Tafel slope of 57.65 mV/dec in 1.0 mol/L KOH,outperforming most of the documented precious-metal-free based electrocatalysts.Benefiting from the in situ formed amorphous NiFeBi layer,it shows excellent stability toward the oxygen evolution reaction(OER).These findings might provide a new way to design advanced precious-metal-free electrocatalysts for OER and the application of electrochemical water splitting.
