Carbon Nanohorn Support for Solar driven CO₂ Reduction to CO Catalyzed by Mn‐complex in an All Earth‐abundant System

Abstract

An Mn‐complex supported on multi‐walled carbon nanotubes (MWCNTs) has been reported to be a superior catalyst for CO2 reduction to CO, where the carbon support strongly influences the catalytic activity, enabling operation at a low overpotential. Here, the effects of various carbon supports on the activity of a Mn‐complex catalyst were investigated. Among the various carbon supports, which included carbon black and MWCNTs, carbon nanohorns (CNHs) were the best support for enhancing the catalytic activity of the Mn‐complex toward CO2 reduction. This enhancement was attributed to the CNHs’ high specific surface area and hydrophobic nature. For solar‐driven CO2 reduction to CO, the Mn‐complex catalyst supported on CNHs was series‐connected to Ni‐doped β‐FeOOH as a water oxidation catalyst via a Si solar cell; a solar‐to‐CO conversion efficiency of 3.3±0.4% was achieved in a single‐compartment reactor.

Toward high‐efficiency photovoltaics‐assisted electrochemical and photoelectrochemical CO2 reduction: Strategy and challenge

“…In particular, we focus on EC and PEC catalysts because carbon compounds are manipulated during CO 2 RR through sequential electron and charge transfer, [22] which are determined by the free Gibbs energy of CO 2 absorption and the desorption energy of the products at the interface of the CO 2 molecules and the catalyst electrode. [19,23,24] Although noble metals are not competitive in terms of industry, gold (Au) and silver (Ag) have many advantages, including low overpotential and high Faradaic efficiency (FE) over a wide range of potentials for the formation of CO from CO 2 , [25][26][27] and can serve as cathode components of PV-EC and PV-PEC because of these advantages. In addition, there is growing interest in non-noble catalysts, including metal-organic framework (MOF)-based and single-atombased catalysts, [28][29][30] which are considered state-of-the-art due to their abundant reserves, unique morphology, reconstruction, superior electron-charge transfer, excellent utilization, and tunable band gap energy.…”

Toward High-Efficiency Photovoltaics-Assisted Electrochemical and Photoelectrochemical CO2 Reduction: Strategy and Challenge

“…In particular, we focus on EC and PEC catalysts because carbon compounds are manipulated during CO 2 RR through sequential electron and charge transfer, [16] determined by the free Gibbs energy of CO 2 absorption and the desorption energy of the products between the interface of the CO 2 molecules and the catalyst electrode. [15,17,18] Although noble metals are not competitive in terms of industry, gold (Au) and silver (Ag) have many advantages, including low overpotential and high Faradaic efficiency (FE) over a wide range of potentials for the formation of CO from CO 2 , [19][20][21] thus, noble metals can serve as cathode parts of PV-EC and PV-PEC because of their advantages. Furthermore, non-noble, metal-organic framework (MOFs)-based, and single-atom-based catalysts as state-of-the-art catalysts [22][23][24] have been described owing to their abundant reserves, unique morphology, reconstruction, superior electroncharge transfer, excellent utilization, and tunable band gap energy.…”