Mo掺杂对CuCo/BNNSs纳米复合材料催化氨硼烷水解活性的影响

Effect of Mo Doping on the Catalytic Activity of CuCo/BNNSs Nanocomposites for Ammonia Boron Hydrolysis

本实验采用共还原法合成了Mo掺杂的非晶态CuCoMo/氮化硼纳米片(记为CuCoMo/BNNSs)复合催化剂,BNNSs通过聚乙烯吡咯烷酮(PVP)辅助氢氧化钠结晶法剥离获得。通过X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)及选区电子衍射(SAED)等对纳米复合催化剂的结构和形貌进行表征,并考察了Mo掺杂对CuCoMo/BNNSs纳米复合催化剂催化氨硼烷(AB)水解产氢活性的影响。结果表明:Mo作为给电子体将电子转移到CuCo NPs,从而增强了催化剂内部金属间的相互作用,提高了催化剂的催化性能。活性测试表明,非晶态(CuCo)0.85 Mo 0.15/BNNSs纳米复合催化剂在室温及pH=14条件下对AB水解产氢的催化活性极高,转化频率(TOF)值高达179.17 mol H 2·mol-1 metal·min-1,首次证明了非晶态CuCoMo NPs是催化AB水解过程中的关键活性组分。这种电子转移不局限于CuCoMo NPs,可以扩展到CuCoW(156.77 mol H 2·mol-1 metal·min-1)和CuCoCr(125.42 mol H 2·mol-1 metal·min-1)NPs。本工作结合表征及实验结果对纳米复合催化剂用于AB水解的催化机理进行了分析。

The Mo-doped amorphous CuCoMo/boron nitride nanosheets(donated as CuCoMo/BNNSs)nanocomposite catalyst was synthesized by co-reduction method,and BNNSs were obtained by polyvinylpyrrolidone(PVP)assisted sodium hydroxide crystallization.The structure and morphology of the nanocomposite catalyst were characterized by X-ray powder diffraction(XRD),fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),transmission electronic microscopy(TEM),high resolution transmission electronic microscopy(HRTEM)and selected area electron diffraction(SAED).Due to Mo doping,the effect of CuCoMo/BNNSs’s catalytic activity for ammonia borane(AB)hydrolysis was investigated.The results showed that Mo acts as an electron donor when transferring electrons to CuCo NPs,which enhances the interaction among metals in the catalyst and improves the hydrolysis performance of AB.The activity test showed that the amorphous(CuCo)0.85 Mo 0.15/BNNSs nanocomposite catalyst had extremely high catalytic activity for hydrolysis of AB under room temperature when pH=14,and the turn over frequency(TOF)value was as high as 179.17 mol H 2·mol-1 metal·min-1.It is demonstrated for the first time that amorphous CuCoMo NPs are key active components in the catalytic hydrolysis of AB.This electron transfer is not limited to CuCoMo NPs,but can also be extended to CuCoW(156.77 mol H2·mol-1 metal·min-1)and CuCoCr(125.42 mol H2·mol-1 metal·min-1)NPs.Moreover,the catalytic mechanism of nanocomposite catalysts for AB hydrolysis was analyzed by combining the characte-rization results with experimental results.