Go Soohyun, Kwon Woosuck, Hong Deokgi, Lee Taemin, Oh Sang-Ho, Bae Daewon, Kim Jeong-Heon, Lim Seolha, Joo Young-Chang, Nam Dae-Hyun
Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea.
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Nanoscale Horiz. 2024 Nov 19;9(12):2295-2305. doi: 10.1039/d4nh00393d.
In the electrochemical CO reduction reaction (CORR), Cu alloy electrocatalysts can control the CORR selectivity by modulating the intermediate binding energy. Here, we report the thermodynamic-based Cu-Sn bimetallic phase control in heterogeneous catalysts for selective CO conversion. Starting from the thermodynamic understanding about Cu-Sn bimetallic compounds, we established the specific processing window for Cu-Sn bimetallic phase control. To modulate the Cu-Sn bimetallic phases, we controlled the oxygen partial pressure (pO) during the calcination of electrospun Cu and Sn ions-incorporated nanofibers (NFs). This resulted in the formation of CuO-SnO NFs (full oxidation), Cu-SnO NFs (selective reduction), CuSn/CNFs, CuSn/CNFs, and CuSn/CNFs (full reduction). In the CORR, CuO-SnO NFs exhibited formate (HCOO) production and Cu-SnO NFs showed carbon monoxide (CO) production with the faradaic efficiency (FE) of 65.3% at -0.99 V ( RHE) and 59.1% at -0.89 V ( RHE) respectively. Cu-rich CuSn/CNFs and CuSn/CNFs enhanced the methane (CH) production with the FE of 39.1% at -1.36 V ( RHE) and 34.7% at -1.50 V ( RHE). However, Sn-rich CuSn/CNFs produced HCOO with the FE of 58.6% at -2.31 V ( RHE). This study suggests the methodology for bimetallic catalyst design and steering the CORR pathway by controlling the active sites of Cu-Sn alloys.
在电化学CO还原反应（CORR）中，铜合金电催化剂可通过调节中间体结合能来控制CORR选择性。在此，我们报道了用于选择性CO转化的多相催化剂中基于热力学的Cu-Sn双金属相控制。从对Cu-Sn双金属化合物的热力学理解出发，我们建立了Cu-Sn双金属相控制的特定工艺窗口。为了调节Cu-Sn双金属相，我们在电纺的含Cu和Sn离子的纳米纤维（NFs）煅烧过程中控制氧分压（pO）。这导致形成了CuO-SnO NFs（完全氧化）、Cu-SnO NFs（选择性还原）、CuSn/CNFs、CuSn/CNFs和CuSn/CNFs（完全还原）。在CORR中，CuO-SnO NFs表现出甲酸盐（HCOO）生成，而Cu-SnO NFs显示出一氧化碳（CO）生成，在-0.99 V（RHE）时法拉第效率（FE）为65.3%，在-0.89 V（RHE）时为59.1%。富铜的CuSn/CNFs和CuSn/CNFs增强了甲烷（CH）生成，在-1.36 V（RHE）时FE为39.1%，在-1.50 V（RHE）时为34.7%。然而，富锡的CuSn/CNFs在-2.31 V（RHE）时生成HCOO，FE为58.6%。本研究提出了双金属催化剂设计方法以及通过控制Cu-Sn合金的活性位点来引导CORR途径的方法。
