Ma Zhanshuai, Wang Bingqing, Yang Xiang, Ma Chao, Wang Weibo, Chen Chengjin, Liang Fangkui, Zhang Nian, Zhang Hui, Chu Yongheng, Zhuang Zhongbin, Xu Haijun, Wang Yu, Liu Junfeng
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China.
J Am Chem Soc. 2024 Oct 23;146(42):29140-29149. doi: 10.1021/jacs.4c11326. Epub 2024 Oct 9.
Atomically dispersed transition metal sites on nitrogen-doped carbon catalysts hold great potential for the electrochemical CO reduction reaction (CORR) to CO due to their encouraging selectivity. However, their intrinsic activity is restricted by the hurdle of the high energy barrier of either *COOH formation or *CO desorption due to the scaling relationship. Herein, we discover a p-block aluminum single-atom catalyst (Al-NC) featuring an Al-N site that enables disentangling this hurdle, which endows a moderate reaction kinetic barrier for *COOH formation and *CO desorption, as validated by in situ attenuated total reflection infrared spectroscopy and theoretical simulations. As a result, the developed Al-NC shows a CO Faradaic efficiency (FE) of up to 98.76% at -0.65 V vs RHE and an intrinsic catalytic turnover frequency of 3.60 s at -0.99 V vs RHE, exceeding those of the state-of-the-art Ni-NC and Fe-NC counterparts. Moreover, it also delivers a partial CO current of 309 mA·cm at 93.65% FE and 605 mA at >85% FE in a flow cell and membrane electrode assembly (MEA), respectively. Strikingly, when using low-concentration CO (30%) as the feedstock, this catalyst can still deliver a partial CO current of 240 mA at >80% FE in the MEA. Considering the earth-abundant character of the Al element and the high intrinsic activity of the Al-NC catalyst, it is a promising alternative to today's transition metal-based single-atom catalysts.
氮掺杂碳催化剂上的原子分散过渡金属位点因其令人鼓舞的选择性，在电化学CO还原反应（CORR）制CO方面具有巨大潜力。然而，由于比例关系，其本征活性受到COOH形成或CO脱附高能垒的限制。在此，我们发现了一种p区铝单原子催化剂（Al-NC），其具有Al-N位点，能够克服这一障碍，为COOH形成和CO脱附赋予适度的反应动力学势垒，原位衰减全反射红外光谱和理论模拟验证了这一点。结果，所开发的Al-NC在相对于可逆氢电极（RHE）为-0.65 V时显示出高达98.76%的CO法拉第效率（FE），在相对于RHE为-0.99 V时本征催化周转频率为3.60 s-1，超过了目前最先进的Ni-NC和Fe-NC同类催化剂。此外，在流动池和膜电极组件（MEA）中，它分别在93.65%的FE下提供309 mA·cm-2的部分CO电流，在FE>85%时提供605 mA的部分CO电流。引人注目的是，当使用低浓度CO（30%）作为原料时，该催化剂在MEA中仍能在FE>80%时提供240 mA的部分CO电流。考虑到Al元素在地壳中的丰富性以及Al-NC催化剂的高本征活性，它是当今过渡金属基单原子催化剂的一个有前途的替代品。
