电镀条件对CoP非晶镀层催化活性的影响

目的考察电镀条件对CoP镀层催化硼氢化钠水解产氢性能的影响规律。方法通过电镀法在铜片表面沉积CoP非晶催化剂,并用于催化硼氢化钠水解制氢。催化剂微观形貌和元素组成分别由场发射扫描电子显微镜(FE-SEM)和能谱仪(EDS)进行表征。通过正交试验确定沉积时间、沉积温度、电流密度对催化剂活性的影响等级。同时,考察了NaBH4浓度、反应温度和循环使用对催化剂性能的影响。结果 FE-SEM和EDS分析表明,CoP镀层由直径200nm左右的晶粒堆积而成,Co与P的原子比为3.6:1。正交实验结果表明,沉积时间对催化剂活性的影响程度最大,之后依次为沉积温度和电流密度。当沉积温度、时间、电流密度分别为20℃、1min、5.56A/dm~2时,所制备的催化剂活性最高。30℃下,6%NaBH_4+2%NaOH体系中,氢气的生成速率为2750mL/(min·g),反应表观活化能为41.2kJ/mol,循环使用4次后,催化剂活性降低64%。结论采用电镀法成功制备了CoP/Cu催化剂,其催化硼氢化钠水解产氢性能优异。电镀条件中,沉积时间是影响催化剂活性的首要因素,其次为沉积温度和电流密度。

Effects of Electroplating Condition on Catalytic Activity of CoP Amorphous Plating

The work aims to investigate influence rule of electroplating condition on catalytic performance of CoP plating for hydrogen generation from hydrolysis of sodium borohydride. CoP amorphous catalysts were deposited on copper sheet through electroplating, and used for hydrogen production from hydrolysis of sodium borohydride. Microstructure and element composition of the catalysts were characterized by using field-emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS), respectively. An orthogonal experiment was performed to investigate level of the influences of deposition time, deposition temperature and current density on catalyst activity. Meanwhile, the influences of NaBH4 concentra- tion, reaction temperature and recycling on the catalyst performance were discussed. The results of FE-SEM and EDS indicated that the CoP coating was piled up with crystalline grain with a diameter of about 200 nm, and the atomic ratio of Co and P was 3.6:1. Orthogonal experiment results showed that the influence degree of these factors was in the following order: deposition time > temperature > current density. The prepared CoP catalyst exhibited the highest activity when the deposition temperature, time and current density was 20℃ , 1 min and 5.56 A/dm2, respectively. Hydrogen generation rate was up to 2750 mL/(min·g) at 30℃ in the system of 6%NaBH4+2%NaOH, and apparent activation energy was 41.2 kJ/mol. After recycling for 4 times, the catalyst activity decreased by 64%. CoP/Cu catalysts exhibiting excellent activity in sodium borohydride hydrolysis are suc-cessfully prepared in the method of electroplating. Among different electroplating conditions, deposition time is the primary factor, followed by deposition temperature and current density.