Indium Cyanamide for Industrial-Grade CO<sub>2</sub> Electroreduction to Formic Acid
Bingquan Jia, Zhe Chen, Chengjin Li, Zhuofeng Li, Xiaoxia Zhou, Tao Wang, Wenxing Yang, Licheng Sun, Biaobiao Zhang
Abstract
Developing industrial-grade electroreduction of CO 2 to produce formate (HCOO – )/formic acid (HCOOH) depends on highly active electrocatalysts. However, structural changes due to the inevitable self-reduction of catalysts result in severe long-term stability issues at industrial-grade current density. Herein, linear cyanamide anion ([NCN] 2– )-constructed indium cyanamide nanoparticles (InNCN) were investigated for CO 2 reduction to HCOO – with a Faradaic efficiency of up to 96% under a partial current density ( j formate ) of 250 mA cm –2 . Bulk electrolysis at a j formate of 400 mA cm –2 requires only −0.72 V RHE applied potential with iR correction. It also achieves continuous production of pure HCOOH at ∼125 mA cm –2 for 160 h. The excellent activity and stability of InNCN are attributed to its unique structural features, including strongly σ-donating [NCN] 2– ligands, the potential structural transformation of [N═C═N] 2– and [N≡C–N] 2–, and the open framework structure. This study affirms metal cyanamides as promising novel materials for electrocatalytic CO 2 reduction, broadening the variety of CO 2 reduction catalysts and the understanding of structure–activity relationships.