Wedged N-doped CuO with more negative conductive band and lower overpotential for high efficiency photoelectric converting CO2 to methanol

• Published in: Applied catalysis. B, Environmental Environmental, 2014-09, Vol.156-157, p.134-140
• Main Authors: Li, Peiqiang, Xu, Jinfeng, Jing, Hua, Wu, Chenxiao, Peng, Hui, Lu, Jing, Yin, Hongzong
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Catalysis; Chemistry; CuO film; Electrochemistry; Exact sciences and technology; General and physical chemistry; Methanol; Photoelectrocatalytic; Photoelectrochemistry. Electrochemiluminescence; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Wedged N-doped CuO
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2014.03.011

The one dimensional wedge-shaped CuO structure was successfully prepared. The current efficiency for PEC reduction of CO2 on wedged N-doped CuO was 14.5 times that of CuO film under −1.2V. Therefore, N-doped CuO exhibits more excellent PEC property for the reduction of CO2. •The N-doped CuO with uniform wedged structure was prepared.•The introduction of N resulted in the negative shift of the conduction band of CuO.•It showed synergistic effect between PC and EC on the target catalyst. One dimensional wedged N-doped CuO has been in situ prepared on Cu substrate by anodization method. The as-prepared material with a length of 786nm and width of 143nm presents uniform wedged structure. The energy band gap and conductive band is 1.34eV and −1.03eV, respectively. The carrier concentration of wedged N-doped CuO (7.5×105m−3) is about 108 times that of CuO film (4.8×10−3m−3). The as-prepared material promotes the separation of photoelectrons and holes efficiently to achieve the excellent photocatalytic reduction property. For the electrochemical properties aspect, the electrochemical adsorptive active site for CO2 on the as-prepared material (25nmol) is 252 times that of CuO film (99pmol). And the overpotential shifts 0.17V positively relative to CuO film. Furthermore, it shows outstanding electrocatalytic property for CO2 reduction. In the process of photoelectrocatalytic reduction CO2, the predominant product is methanol, the current efficiency on wedged N-doped CuO electrode (84.4%) is 14.5 times that of CuO film (5.84%), the methanol output (3.6mmolL−1cm−2) is 139 times that of CuO film (0.026mmolL−1cm−2). In addition, it shows that the methanol output in the photoelectrocatalytic process is 1.3 times of the simple addition of photocatalytic process and electrocatalytic process, which indicates the distinct 1+1>2 synergistic effect between electrocatalytic reduction and photocatalytic reduction.