g-C3N4和Pt/g-C3N4在常温常压电化学合成氨中的阴极催化性能

摘要

电化学法合成氨是一种有希望替代传统Haber-Bosch法的新方法，而开发一种能够高效活化N₂分子的催化剂成为电化学法合成氨的关键。采用一步煅烧二氰二胺的方法制备了石墨型氮化碳（g-C₃N₄），并将Pt纳米颗粒沉积在g-C₃N₄上制备了Pt/g-C₃N₄。采用XRD、SEM、TEM以及XPS表征和分析了所得催化剂的晶体结构，表面微观形貌和表面元素组成。分别采用H⁺型Nafion膜和H⁺/NH₄⁺型Nafion膜作电解质，研究了Pt/g-C₃N₄和g-C₃N₄的催化性能以及Nafion膜中NH₄⁺的作用。结果表明，Pt/g-C₃N₄和g-C₃N₄分别作阴极催化剂时均成功合成出NH₃，而Pt/g-C₃N₄的性能优于g-C₃N₄。另外，膜中引入NH₄⁺能够促进N₂的电化学还原。

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	胡红伟
	张文
	王宇新

关键词：电化学合成氨氮化碳铂 Nafion膜常温常压

Abstract：

Electrochemical ammonia synthesis has been regarded as a promising alternative to the present Haber-Bosch process for ammonia production, and the development of efficient catalyst for N₂ reduction is key to the electrochemical method. In this research, g-C₃N₄ catalyst is prepared by the thermal polycondensation process, and Pt/g-C₃N₄ catalyst is obtained by reducing Pt onto g-C₃N₄ nanosheets with ethylene glycol. The phase composition and morphology of the two kinds of catalysts are characterized by XRD, SEM, TEM and XPS. The catalytic performance of Pt/g-C₃N₄ and g-C₃N₄ in a polymer electrolyte membrane cell is studied using Nafion membranes in H⁺ or H⁺/NH₄⁺ form, respectively. While both Pt/g-C₃N₄ and g-C₃N₄ show certain activity towards ammonia synthesis from H₂ and N₂ gases under ambient temperature and pressure, Pt/g-C₃N₄ leads to higher ammonia yield under the same conditions. The yield of ammonia appears to be higher with the H⁺/NH₄⁺-form Nafion membrane, suggesting the presence of NH₄⁺ in the membrane, facilitates the electrochemical reduction of nitrogen.

Keywords： electrochemical synthesis of ammonia； carbon nitride； platinum； Nafion membrane； ambient temperature and pressure

Received 2016-04-28;

Corresponding Authors: 王宇新,E-mail:yxwang@tju.edu.cn。 Email: yxwang@tju.edu.cn

About author: 胡红伟(1990-),男,硕士研究生,现从事电化学方面的研究。

引用本文:

胡红伟, 张文, 王宇新.g-C₃N₄和Pt/g-C₃N₄在常温常压电化学合成氨中的阴极催化性能[J]. 化学工业与工程, 2018,35(1): 22-28

Hu Hongwei, Zhang Wen, Wang Yuxin.Performance of g-C₃N₄ and Pt/g-C₃N₄ Cathode Electrocatalyst in Electrochemical Ammonia Synthesis[J]. Chemcial Industry and Engineering, 2018,35(1): 22-28

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