Novel titanium dioxide catalyst support for electrocatalytic carbon dioxide reduction

To address this challenge, a team of researchers, led by Mr. Kai Takagi and Prof. Chiaki Terashima from Graduate School of Science and Technology and Research Institute for Science and Technology at Tokyo University of Science (TUS) in Japan, has recently developed a catalyst support based on titanium dioxide (TiO₂) powder, a compound commonly used in sunscreen, paints, coatings, toothpaste, plastics, paper, pharmaceuticals, and food coloring, as an alternative to carbon for facilitating effective CO₂reduction. Their work was made available online on 4 August 2023 and published in Volume 902 of the journal科学的e Total Environmenton 1 December 2023.

The researchers first carried out surface treatment using safe and inexpensive in-liquid plasma to improve the electrochemical properties of TiO₂. "The in-liquid plasma-treated TiO₂maintained its particle shape and crystal structure. Additionally, elemental analysis and evaluation of the interfacial bonding state and electrochemical properties of TiO₂revealed that the redox peaks corresponding to Ti⁴⁺and Ti³⁺derived from TiO₂disappeared and the hydrogen overvoltage decreased," highlights Prof. Terashima.These observations led the team to conclude that tungsten coating or doping occurred on some portions of the reduced TiO₂surface.

The researchers then used the TiO₂as a carrier and loaded it with silver nanoparticles (AgNPs), which act as catalysts, to develop a gas diffusion electrode for CO₂reduction. While untreated TiO₂exhibited high selectivity for CO₂and carbon black, in-liquid plasma-treated TiO₂with 40 wt% AgNP loading demonstrated increased hydrogen production and enhanced catalytic performance. Given that a suitable ratio of hydrogen to carbon monoxide is important for effective CO₂reduction, the presented technology, thus, has tremendous potential for converting CO₂to useful byproducts, such as syngas, which is considered a clean fuel with very high industrial value.

Additionally, the electrocatalytic reduction of CO₂can be integrated with renewable energy sources, such as solar panels or wind power, for sustainable and environmentally friendly CO₂conversion. Therefore, this work is a significant step towards efficiently tackling greenhouse gas emissions and fighting climate change.

"Hopefully, the present study will promote research on technologies for carbon neutrality and carbon recycling, in alignment with the United Nations Sustainable Development Goals 7, 12, and 13 on affordable and clean energy, responsible consumption and production, and climate action, respectively. These, in turn, will open doors to the realization of a carbon-neutral and sustainable future," concludes Prof. Terashima.