Development of CO2 reduction technique by controlling the overpotential for hydrogen evolution at the a-C surface

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02845
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Yamaguchi University
• Principal Investigator: Honda Kensuke 山口大学, 大学院創成科学研究科, 教授 (60334314)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: アモルファスカーボン / 二酸化炭素還元 / 電極触媒 / 光触媒

Outline of Final Research Achievements

Objective of this study is to realize electrocatalyst and photocatalysts for CO2 reduction with higher efficiency and higher durability.
Amorphous carbon was selected as electrode material because amorphous carbon shows the higher over potentials for H2 evolution and the extremely higher physical and chemical stability. Nitrogen atoms was selected as a dopant atom because the over potential for H2 evolution was highest using nitrogen. a-C electrocatalysts for CO2 reduction was successfully fabricated by introducing amino groups and carbonyl groups on the N-doped a-C surface as active sites for CO2 reduction. The current efficiency for CO2 reduction on the a-C electrocatalyst was extremely high and was 95%, and the CO2 reduction current was stable and the decrease rate after 6 hours was 7%.
It was summarized that a-C electrocatalysts for CO2 reduction with higher efficiency and higher durability was able to be realized.

Free Research Field

プラズマ材料科学

Academic Significance and Societal Importance of the Research Achievements

電気化学および光電気化学的手法を用いてCO2をギ酸への変換を可能とする本研究の成果は、大気中のCO2濃度を低減可能であり、ギ酸を資源に利用可能なため、環境と資源・エネルギーの問題を同時に解決可能となる技術である。また、CO2からギ酸への還元反応は、標準電位が－0.61Vであり、水素生成反応の標準電位(0V)より卑電位側であるため、水溶液中で水素生成反応の阻害を受けずにCO2を還元することは困難である。本研究のa-Cを用いた水素生成反応の抑制制御と活性サイト賦与によるCO2還元触媒の具現化手法は、高活性と高耐久性を併せ持つCO2還元触媒を具現化する新たな手法であり、新たな触媒の設計指針となる。