利用無電鍍法製備Co–Ni–P薄膜應用於氫催化劑

The Study of Co–Ni–P for Hydrogen Generation by Application Using Electroless Plating

李啟聖(Chi-Sheng Li)

指導教授 ： 謝淑惠

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2014年)

摘要

摘要
本研究利用低成本、易操作的無電鍍法於銅基材上製作Co-Ni-P合金薄膜(以下簡稱ECo-Ni-P)，作為有效化學儲氫材料產氫觸媒以取代Pt、Au、Ru和Rh等貴金屬觸媒，以降低產氫成本。Co-Ni合金觸媒固定在銅基材，由於結合性良好可重覆使用產氫，且可避免粉末不易回收造成環境二次汙染。
在鹼性硼氫化鈉溶液中利用ECo-Ni-P的觸媒特性，使其產生化學還原和催化水解反應生成氫氣，而本研究改變無電鍍參數得到較佳的產氫速率。本研究中改變硼氫化鈉濃度由2wt%到20 wt%的鹼性硼氫化鈉溶液，在以相同條件之試片作測試，發現當硼氫化鈉的重量百分比的增加會使得氫氣產量也隨之增加；但硼氫化鈉增加到10wt%有最佳的產氫速率，因此產氫實驗均選用10wt%鹼性硼氫化鈉溶液來做測試。
實驗中改變無電鍍製程參數：pH值7、8和9，以及無電鍍溶液Ni和Co金屬鹽類之比例1:1、1:3和1:5，探討ECo-Ni-P薄膜的特性和產氫效果。研究結果發現1：1在pH7、8有利於鎳析出，鈷在pH9易析出，磷則不受pH值影響。當金屬鹽Ni2+和Co2+比例提高為1：3和1：5時，受到濃度影響鎳在pH7和8均不易析出，唯高pH9時可少量析出。鈀元素為前處理活化金屬，當鈷鎳析鍍不易，自然明顯含量提高。ECo-Ni-P以金屬離子比1：5(Ni2+ / Co2+)和pH9的實驗參數下有最佳產氫效果。雙金屬催化劑Co-Ni-P比Co-P和Ni-P更好，最佳達到18609ml/g/min。本研究發現利用電鍍所製備出來Ni、Co或Co-Ni合金薄膜與銅基板的鍵結效果較差且經過長時間使用會有脫落的現象。而利用無電鍍所製備出來的Co-Ni-P薄膜與銅基板有良好的結合，經過長時間12小時和二次使用也不易脫落。

關鍵字

無電鍍 ； 無電鍍Co-Ni-P ； 硼氫化鈉 ； 氫氣製備

並列摘要

Abstract
The increasing demand of Hydrogen follows with the application of Fuel cell, there are many methods to acquire hydrogen such as water electrolysis, ethanol steam vreforming, hydrolysis of hydrazine borane and sodium borohydride (NaBH4), etc., among them, the hydrolysis of NaBH4 is regarded as an efficient method to produce hydrogen due to its high hydrogen storage capacity (10.8 wt%), and good stability under ordinary conditions in solid state and solution.
Currently, the noble metal Pt, Au, Ru and Rd metal are the most efficient metal as catalysts for hydrogen generation using sodium borohydride solution. In this study, Co-Ni-P films were deposited on a Cu substrate in a bath containing Co+2 and Ni+2 ions by using electroless plating, to replace the noble metals for hydrogen generation application. Electroless Co-Ni-P plating was investigated by changing Ni2+/Co2+ molar ratio from 1:1, 1:3 to 1:5, in respective plating process, which the total quantity of Co2+ and Ni2+ in plating bath is kept at 0.02 mol; the pH of bath from 7, 8 to 9, separately. The deposited Co-Ni-P films were characterized by using Field Emission electron microscope, energy dispersive X-ray spectrometer, and hydrolysis experiment for their microstructure, crystal structure, and catalyst properties.
The experimental results show that the Co-Ni-P films were composed of nanoparticles at the initial stage (about 20 sec). The Co was mainly deposited at pH 8 and 9. The Co-Ni-P films deposited at the pH of bath 9, Ni2+/Co2+ molar ratio 1:1, 1:3 to 1:5 are amorphous structure and contain about Co(46.57 at%), Ni (39.63 at%), and P (13.8 at%); Co(52.42 at%), Ni (4.3 at%), Pd(23.97 at%), and P (19.31 at%); and Co(62.62 at%), Ni (8.13 at%), Pd(10.86 at%), and P (18.39 at%), respectively. The hydrogen generation by using Co-Ni-P films which were deposited at the pH of bath 9, Ni2+/Co2+ molar ratio 1:5 as catalyst could reach 18609ml/g/min。And there is good adhesion between the Co-Ni-P films and Cu substrate, the Co-Ni-P films could be reused as catalyst for hydrogen generation for 12 hours.

並列關鍵字

Electroless Co–Ni–P plating ； Sodium borohydride ； Hydrogen generation ； Electroless plating

參考文獻

[19] 劉宣佑，2009，「電鍍與無電鍍析鍍鈷鎳薄膜之研究」，國立虎尾科技大學材料科學與綠色能源研究所碩士論文。

[20] 楊睿瑜，2010，「鎳鈷磷合金無電鍍製程及性質研究」，國立台北科技大學材料科學與工程研究所碩士論文。

[1] M. Hook, X. Tang, 2013, “Depletion of fossil fuels and anthropogenic climate change—A review”, Energy Policy 52 797–809.

[2] D.A.J. Randa, R.M. Dellb, 2005, “The hydrogen economy: a threat or an opportunity for lead–acid batteries?” , Journal of Power Sources 144 568–578.

[3] J. Zhang a , T.S. Fisher, Jay P. Gore, D. Hazra,P. V. Ramachandran, 2006, “Heat of reaction measurements of sodium borohydride alcoholysis and hydrolysis”, International Journal of Hydrogen Energy 31 2292–2298.