Highly efficient water splitting and carbon dioxide reduction into formic acid with iron and copper powder

Pd/C-catalyzed reduction of NaHCO 3 into CH 3 COOH with water as a hydrogen source

“…It has been reported that the formate adsorption enthalpy on the Pd, Cu and Ni follows the order of Cu (110) < Pd (110) < Ni (110) [35], which suggest that the formate adsorption enthalpy on Cu is the lowest, that is Cu can catalyze the HCOOH formation effectively. This is in accordance with our previous research, in which a HCOOH yield of 76% was obtained with the catalyst Cu [18]. On the other hand, Ni has the largest formate adsorption enthalpy among Cu, Pd and Ni, suggesting that more reduced products than HCOOH can be obtained on the Ni catalyst according to the proposed mechanism (Scheme 1).…”

“…To further examine the above proposed reaction mechanism, the adsorption enthalpies of the intermediate of formate on the Pd, Cu and Ni were compared by referring the data from literature, and our previous research, in which the HCO 3 − was mainly reduced into C 1 products when Cu or Ni as the catalyst [18,20,33]. It has been reported that the formate adsorption enthalpy on the Pd, Cu and Ni follows the order of Cu (110) < Pd (110) < Ni (110) [35], which suggest that the formate adsorption enthalpy on Cu is the lowest, that is Cu can catalyze the HCOOH formation effectively.…”

“…In previous research of hydrothermal reduction of CO 2 , the products were mainly C 1 compounds such as HCOOH and CH 3 OH [18][19][20]. Although there have been reports of synthesis of long carbon-chain organics from CO 2 for hydrogenation and electro- chemical reduction [23][24][25], synthesis of C 2 compounds using hydrothermal methods has not been well studied.…”

“…Previous research have demonstrated that CO 2 or NaHCO 3 can be reduced into organic chemicals such as CH 4 , HCOOH and CH 3 OH effectively and efficiently under hydrothermal condition with earth abundant metallic materials such as Fe, Al, and Zn [17][18][19][20]. In such hydrothermal CO 2 reduction, the required hydrogen source comes from the in-situ reaction of high temperature water (HTW).…”

“…Therefore, the metal reductants can be recycled with renewable energies. Although hydrothermal reactions are usually operated under high temperatures (200-350 • C), the reactions of CO 2 reduction are exothermic with a metal reductant [18], which means they can be potentially self-supported. Thus, the hydrothermal reduction of CO 2 into organic chemicals could be one promising and efficient method to help alleviating the problem of global warming and provide alternative and potentially sustainable chemical feedstock instead of the traditional fossil fuel-based feedstock.…”