Efficient electrocatalytic urea synthesis from CO_(2)and nitrate over the scale-up produced FeNi alloy-decorated nanoporous carbon

Electrocatalytic urea synthesis provides a favorable strategy for conventional energy-consuming urea synthesis,but achieving large-scale catalyst synthesis with high catalytic efficiency remains challenging.Herein,we developed a simple method for the preparation of a series of FeNi-alloy-based catalysts,named FeNi@nC-T(n represents the content of nanoporous carbon as 1,3,5,7 or 9 g and T=900,950,1000 or 1100°C),for highly performed urea synthesis via NO_(3)−and CO_(2)co-reduction.The FeNi@7C-1000 achieved a high urea yield of 1041.33 mmol h^(−1)gFeNi^(−1)with a Faradaic efficiency of 15.56%at–1.2 V vs.RHE.Moreover,the scale-up synthesized FeNi@7C-950-S(over 140 g per batch)was achieved with its high catalytic performance and high stability maintained.Mechanism investigation illuminated that the Ni and Fe sites catalyze and stabilize the key*CO and*N intermediates and minimize the C–N coupling reaction barriers for highly efficient urea synthesis.

一种螺旋锥齿轮齿面接触区和传动误差的全局优化方法(英文)

目的:传统的齿面接触分析技术存在调整参数繁多、控制目标不明确和不包含传动误差优化等缺陷。本文旨在提出一种齿面接触区和传动误差的全局优化设计方法,以得到满足齿轮传动性能要求的小轮产形轮节锥参数及机床调整参数。创新点:1.提出了新的确定各节锥参数之间几何关系的计算公式,并建立了节锥参数与曲率参数的相关公式;2.提出以齿面接触区长半轴、接触线方向角和传动误差曲线交点纵坐标为优化目标,以齿面法曲率和短程挠率为控制参数,以复合形法约束处理的遗传算法为求解途径的齿面接触特性全局优化设计方法。方法:1.分析常见齿面接触区和传动误差曲线的缺陷及其原因(图1);2.提出全局优化目标(图2),进行节锥参数和曲率参数分析,从而确定控制参数(图3~6),建立优化方程并进行求解算法分析(图7和8),然后进行实例计算分析(图9和10);3.建立齿轮副传动系统有限元分析模型,验证优化方法的正确性(图11~13)。结论:1.优化设计的实例分析表明,优化目标、控制参数和优化算法具有良好的匹配性;2.通过优化目标与控制参数的相关性分析,得出了控制参数的影响特征;3.通过有限元分析验证,优化设计结果达到了预期的齿轮传动性能指标。