Among carbon dioxide (CO₂) conversion technologies, electrocatalytic CO₂ reduction reaction (CO₂RR) offers a promising route for realizing renewable energy storage and carbon neutralization. In addition, formate, a salt or compound of formic acid generated by CO₂RR, has evolved into a valuable commodity. Formate is now widely used in the leather and pharmaceutical industries and has become an economically important feedstock for animals. In addition, it is considered an excellent hydrogen storage carrier and provides the raw material for direct formic acid fuel cells, which power small, portable electronics such as phones, as well as larger fixed power applications and vehicles.

Due to its environmentally friendly properties and low costs, researchers have been exploring how the metal tin (Sn) and its oxide can be used in formate production. However, to date, the methods suggested generally involve complex processes and lengthy production times, which restrict their large-scale industrial application.

In a study published in the KeAi journal Green Chemical Engineering, researchers used a one-step electrochemical anodic oxidation (AO) method to synthesize the nanoporous tin oxide using tin foil as the raw material. AO is a scalable, simple, and efficient alternative for the preparation of nanoporous tin oxide, providing large specific surfaces, high porosity, and abundant grain boundaries. The researchers achieved a formate partial current density of 285 mA·cm^-2 in a flow cell, with selectivity of 96.4 percent.

Co-corresponding author Sheng Zhang, from Tianjin University in China, explains: “Using nanoporous tin oxides in this process increased the selectivity of formate. In addition, in combination with flow cell architecture, we were able to simultaneously achieve high formate selectivity and current density. Importantly, this process didn’t involve complex preparation processes and a large time investment, which makes it a promising candidate for large-scale industrial production.”

- This press release was provided by KeAi Communications Co.