Due to the extensive use of non-renewable fossil fuels, the crisis in energy is growing, and the gas CO₂, which is a product of the burning of hydrocarbons, is contributing to global warming and to acidification of the oceans. Therefore, the issue about carbon dioxide (CO₂) capure, sorage and utilization has inspired intensive interests. ^[2,3] In the various methods of CO₂ utilization and recycling, electrochemical reduction of CO₂ to transform to useful chemicals or fuels is a potentially efficient way. However, in the procesure of CO₂ electroreduction, there is a challenge of the slow kinetic of CO₂ electroreduction. ^[4,5] Overcoming the problems of CO₂ reduction under mild conditions would enable solve the energy crisis and the global warming.

In the past few decades, researchers found that many metal oxide nanopowders could be the perfect catalysts in the CO₂ electroreduction for their controllable various morphologies.^[1] In this work, we report the synthesis of SnO_x nanocatalysts loaded on the multi-walled carbon nanotubes (MWCNTs), which electrochemical catalyzed CO₂ to formate, HCOOH, on the room-temperature with an electrochemical cell having a catalytic SnO_x cathode. We controlled different special morphologies by one-step hydrothermal method from SnCl₂ precursors. The highest faradaic and energy efficiencies of 65% and 28% were obtained at −1.40 V vs. SCE with particles that were obtained by KOH reduction from a SnCl₂ precursor and showed excellent stability in prolonged electrolysis.

References

[1]C. Zhao, J.L. Wang, J.B. Goodenough Chemical Communication, 52,12175(2016).

[2] R. Williams, R.S. Crandall, A. Bloom, Applied Physics Letters, 33,381 (1978).

[3] A.S. Agarwal, Y. Zhai, D. Hill, N. Sridhar, ChemSusChem, 4,1301 (2011).

[4] M. Gattrell, N. Gupta, A. Co, Energy Conversion and Management, 48,1255 (2007).

[5] N. S. Spinner, J. A. Vega and W. E. Mustain, Catalysis Science & Technology, 2,19(2012).