《厦门大学学报（自然科学版）》

甲酸分解制氢是解决能源问题的有效途径,与Pd催化剂相比,Au催化剂不易失活,具有较好的稳定性.使用次亚磷酸钠原位还原制备了Au-P/SiO2催化剂,并利用X射线衍射、透射电子显微镜和X射线光电子能谱等表征手段探讨其结构,并以甲酸分解为目标反应研究其催化性能.结果表明,该方法制备的催化剂中Au粒子(粒径3 nm左右)均匀分散在SiO2表面,且P掺杂进入Au的晶格形成Au-P复合物,改变了Au的电子结构.同时反应过程中产生的PⅢ被Au3+氧化生成磷酸金,提供酸性中心,使Au-P/SiO2催化剂表现出较Au/SiO2催化剂更加优越的催化性能.在363 K,4 mol/L的甲酸溶液中,Au-P/SiO2催化剂催化甲酸分解的转化率可达51%,是未掺杂的Au/SiO2催化剂的4倍.

Formic acid decomposition is an effective way to solve energy problem.Compared with Pd catalysts,Au catalysts have better anti-inactivation ability.In this article,Au-P/SiO2 catalysts were prepared with in situ reduction using NaH2PO2.The catalysts were characterized by X-ray diffraction,transmission electron microscope,X-ray photoelectron spectroscopy,and catalytic performances of the catalysts were tested through catalytic decomposition of formic acid.The results of the catalyst characterization demonstrated that with this method, the Au particles(3 nm)highly dispersed on the surface of SiO2,and some P entered into the crystal lattice of Au,which contributed the formation of Au-P compound and changed the electrical property of Au.Meanwhile,in the process of reaction,PⅢ appeared,and it was oxidized into PⅤ by Auδ+ to form gold phosphate with acid-base properties.For the reasons above,Au-P/SiO2 is more active than Au/SiO2.In 363 K,4 mol/L formic acid solution,the conversion rate of formic acid reached 51% over Au-P/SiO2,which is 4 times of Au/SiO2.

引言
1 实验部分
2 结果与讨论
3 结论

图1 Au/SiO2(a)和Au-P/SiO2(b)催化剂的TEM图<br/>Fig.1 TEM images of Au/SiO2(a)and Au-P/SiO2(b)

图1 Au/SiO2(a)和Au-P/SiO2(b)催化剂的TEM图
Fig.1 TEM images of Au/SiO2(a)and Au-P/SiO2(b)

图2 Au粒子在SiO2表面生长的可能过程<br/>Fig.2 Possible growth process of Au particle on the surface of SiO2

图2 Au粒子在SiO2表面生长的可能过程
Fig.2 Possible growth process of Au particle on the surface of SiO2

图3 Au标准XRD卡片(a),Au/SiO2(b),Au-P/SiO2(c)和反应一轮后Au-P/SiO2(d)催化剂的XRD谱图<br/>Fig.3 Standard card of Au(a),XRD patterns of Au/SiO2(b),Au-P/SiO2(c)and Au-P/SiO2 after decomposition of formic acid(d)

图3 Au标准XRD卡片(a),Au/SiO2(b),Au-P/SiO2(c)和反应一轮后Au-P/SiO2(d)催化剂的XRD谱图
Fig.3 Standard card of Au(a),XRD patterns of Au/SiO2(b),Au-P/SiO2(c)and Au-P/SiO2 after decomposition of formic acid(d)

图4 新制催化剂和反应一轮后Au-P/SiO2催化剂的Au-4f(a)和P-2p(b)的XPS谱图<br/>Fig.4 XPS spectra of Au-4f(a)and P-2p(b)of the catalysts before and after decomposition of formic acid125.7

图4 新制催化剂和反应一轮后Au-P/SiO2催化剂的Au-4f(a)和P-2p(b)的XPS谱图
Fig.4 XPS spectra of Au-4f(a)and P-2p(b)of the catalysts before and after decomposition of formic acid125.7

图5 不同浓度还原剂制Au-P/SiO2催化剂的XRD谱图(a)和甲酸转化率(b)<br/>Fig.5 XRD patterns of Au-P/SiO2 catalysts prepared in different mole ratio of H2PO2- and AuCl4-(a),and plot of formic acid conversion rate versus mole ratio of H2PO2- and AuCl4-(b)

图5 不同浓度还原剂制Au-P/SiO2催化剂的XRD谱图(a)和甲酸转化率(b)
Fig.5 XRD patterns of Au-P/SiO2 catalysts prepared in different mole ratio of H2PO2- and AuCl4-(a),and plot of formic acid conversion rate versus mole ratio of H2PO2- and AuCl4-(b)

图6 不同浓度还原制备Au-P/SiO2催化剂的TEM图<br/>Fig.6 TEM images of Au-P/SiO2 catalysts prepared in different mole ratio of H2PO2- and AuCl4-

图6 不同浓度还原制备Au-P/SiO2催化剂的TEM图
Fig.6 TEM images of Au-P/SiO2 catalysts prepared in different mole ratio of H2PO2- and AuCl4-

表1 Au-P/SiO2催化剂的循环利用<br/>Tab.1 Recycling of formic acid decomposition catalyzed over Au-P/SiO2

表1 Au-P/SiO2催化剂的循环利用
Tab.1 Recycling of formic acid decomposition catalyzed over Au-P/SiO2

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备注

引言

1 实验部分

2 结果与讨论

3 结论

学报简介

备注

引言

1 实验部分

2 结果与讨论

3 结 论

学报简介

3 结论