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    多孔碳负载Ru催化剂的制备及其催化硼氢化钠水解制氢性能

    Preparation of Ru catalyst supported on porous carbon and its performance in catalyzing sodium borohydride hydrolysis for hydrogen production

    • 摘要: 全球能源转型背景下,氢能成为清洁能源焦点。硼氢化钠(NaBH4)因其卓越的储氢特性和室温可控释氢特性,被视为移动供氢设备的理想介质,但其水解动力学缓慢制约实际应用,需开发高效纳米催化剂突破瓶颈。采用氧化镁硬模板法耦合氢氧化钾活化法,得到具有介孔−微孔三维多级孔道结构的多孔碳载体(MKC),再负载贵金属Ru制备得到催化剂Ru/MKC。采用SEM、TEM、XRD、XPS、BET等表征技术系统分析催化剂微观结构,并通过水解动力学测试和循环稳定性测试以评估其催化NaBH4水解制氢性能。探究了不同多孔碳载体、不同Ru负载量、NaBH4浓度、NaOH浓度和温度对催化性能的影响,深入分析了多孔碳载体与催化性能之间的关系。结果表明:Ru/MKC催化剂具有更好的催化性能,相较于其他催化剂放氢速率提高了约5倍,当Ru负载量为10%,测试条件为1% NaBH4,1% NaOH,常温303 K时,产氢速率出现峰值10 980 mL/(min·g),周转频率高达495 min−1,活化能仅为63.4 kJ/mol,具有良好的循环稳定性,在5次测试后性能仍能保持67%。这种优异的催化性能主要得益于Ru/MKC的介孔、微孔多级孔道结构和高比表面积(1 900 cm2/g),其中介孔可以加速传质速率,微孔为负载Ru纳米颗粒提供更多缺陷位点,能够实现Ru纳米颗粒的高效负载和均匀分布,显著提升催化活性位点密度与电子传导效率,从而有效增强催化性能。

       

      Abstract: Hydrogen energy, as a zero-carbon efficient energy, has promoted the development of NaBH4 hydrolysis hydrogen production technology, but kinetic bottleneck needs to be broken through by efficient catalysts. In this study, a multi-level porous carbon MKC with both mesopores and micropores was prepared template method combined with KOH activation, and Ru nanoparticles were loaded (Ru/MKC). Characterization (SEM/TEM/XRD/XPS/BET) showed that Ru/MKC had a significant optimization of mass transfer and active site density due to the synergistic effect of multi-level porosity (specific surface area 1 900 cm2/g) and uniform dispersion of Ru. Performance test showed that the hydrogen production rate of Ru/MKC under the condition of 303 K and 1% NaBH4/ 1% NaOH (10 980 mL/(min·g)) was 5 times higher than that of the sample, with low activation energy of 63.4 kJ/mol and the activity remained at 67% after 5 cycles. The performance advantage was attributed to mesopores accelerated the diffusion of reactants, micropores provided high-density defect anchoring Ru particles, and the problem of mass transfer limitation in pure micropores and loading in pure mesopores was solved simultaneously, achieving dual optimization of electron conduction and catalytic sites.

       

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