College of Chemistry and Chemical Engineering,Xi′an University of Science and Technology
Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources

开发高效、低成本的清洁能源,有助于降低CO2排放。电催化分解水产氢产氧或许可实现未来对清洁能源的需求。在诸多纳米材料中,超薄二维纳米材料因其可暴露更多的活性位点、具有更高的比表面积等特点,在电催化反应中表现出优异的性能。镍铁水滑石(NiFe-LDH)是非常有前景的过渡金属电催化分解水产氧反应(OER)催化剂。采用水热法制备NixFe1-LDH(x=1,2,3)前体,利用超声悬浮剥离法实现超薄超小镍铁水滑石纳米片的快速制备。声悬浮法利用超声波发射端和反射端间产生的高强度声辐射力来抵消样品的重力,进而使样品被悬浮。超声波反复叠加形成的高声强驻波,更易实现超薄超小纳米材料的快速制备。研究发现,通过超声悬浮技术可实现仅用20μL甲酰胺在20min内成功将Ni1Fe1-LDH前体从横向尺寸为1500nm、厚度为25.66nm剥离为分散较为均匀、横向尺寸约10nm、厚度低至0.649nm的超薄超小镍铁水滑石纳米片,并具有优异的OER性能。不同物质的量比的镍铁水滑石随超声悬浮时间逐渐增加,OER性能逐渐提高。其中,当电流密度达10mA/cm2时,Ni1Fe1-LDH-20min的过电位低至309mV,相比于Ni1Fe1-LDH前体的过电位673mV,降低了364mV,其塔菲尔斜率也相应从137mV/dec降至67mV/dec,电化学活性表面积增大了2.4倍。与其他过渡金属基催化剂相比,在OER中表现出优异的性能。

The development of efficient and low-cost clean energy contributes to the reduction of CO2 emissions. Hydrogen and oxygen production from electrocatalytic water splitting may be a promising solution to the future demand for clean energy. Among many nanomaterials,ultrathin two - dimensional materials have shown excellent performance in electrocatalytic reactions due to the fact that they canexpose more active sites and have higher specific surface area. Nickel-iron layered double hydroxide (NiFe-LDH) is a very promisingtransition metal electrocatalytic catalyst for oxygen evolution reaction (OER). Therefore, NixFe1-LDH(x = 1,2,3) precursors were synthesized by hydrothermal method, then the ultra-thin and ultra-small LDH nanosheets were quickly synthesized by acoustic levitation. Theacoustic levitation method utilizes the high-intensity acoustic radiation force generated between the emitting and reflecting ends of ultrasound to counteract the gravity of the sample, which in turn levitated the sample. The high acoustic intensity standing wave formed by repeated superposition of ultrasound waves makes it easier to realize the rapid preparation of ultra-thin and ultra-small nanomaterials. It isfound that the Ni1Fe1-LDH precursor could be successfully exfoliated into ultra-thin and ultra-small hydrotalcite nanosheets with only20 μL formamide within 20 min by acoustic levitation. The transverse size of the Ni1Fe1-LDH precursor is 1 500 nm and the thickness is25.66 nm. The ultra-thin and ultra-small Ni1Fe1 -LDH-20 min transverse size is 10 nm, and the thickness is as low as 0.649 nm. Itshows excellent OER catalytic performance. For different molar ratios of nickel-iron hydrotalcites, with the increasing of the acoustic levitation time, the OER properties is improved. When the current density reaches 10 mA/ cm2, the overpotential of Ni1Fe1-LDH-20 min is309 mV, compared to the overpotential of 673 mV of Ni1Fe1-LDH precursor, it decreases by 364 mV. The tafel slope decreased from 137to 67 mV/ dec, and the electrochemically active surface area was increased by 2.4 times. Compared with other transition metal-based catalysts, it demonstrates excellent performance in OER.

国家自然科学基金资助项目(22179107)

加晓丹,李金龙,张绍炳,等.超薄超小镍铁水滑石的声悬浮制备[J].洁净煤技术,2024,30(4):120-129.

JIA Xiaodan,LI Jinlong,ZHANG Shaobing,et al.Preparation of ultra-thin and ultra-small nickel-iron layered double hydroxide by acoustic levitation[J].Clean Coal Technology,2024,30(4):120-129.