(376c) Engineering High Performance and Durable PGM-Free Electro-Catalysts for Oxygen Evolution Reaction in PEM Water Electrolysis
- Conference: AIChE Annual Meeting
- Year: 2017
- Proceeding: 2017 Annual Meeting
- Group: Topical Conference: Nanomaterials for Applications in Energy and Biology
- Time: Tuesday, October 31, 2017 - 1:06pm-1:24pm
In line with this objective, exploiting theoretical first principles approaches, we have engineered anionic fluorine (F) doped transition metals non-oxide pnictide (TMN) based electro-catalyst for OER in PEM water electrolysis. The dopant-F plays a vital role in enhancing the electro-catalytic activity by altering the electronic structure of the electro-catalyst. The as-synthesized electro-catalyst with F content of 10 wt. % consequently exhibits excellent electro-catalytic performance, outperforming the benchmark IrO2 for OER in PEM water splitting. The as-synthesized electro-catalyst powder was coated on porous titanium (Ti) substrate (total catalyst loading=1 mg/cm2) and used as an anode. Electrochemical characterization of the electro-catalyst has been carried out in three-electrode configuration system, using 1N sulfuric acid (H2SO4) solution as the proton source as well as the electrolyte. Pt wire and Hg/Hg2SO4 are used as a counter electrode and reference electrode (+0.65 V with respect to the normal hydrogen electrode, NHE) respectively. Electrochemical evaluation has been conducted at a scan rate of 10 mV/sec and at temperature of 40oC. The generated PGM-free electro-catalyst exhibits an onset potential of ~1.43 vs NHE, similar to that of IrO2 but significantly lower charge transfer resistance (Rct) than benchmark IrO2. In addition, the as-synthesized electro-catalyst with F content of 10 wt. % displays a remarkable ~1.4 fold higher electro-catalytic OER activity (i.e. current density at 1.5 V) than that of IrO2 approaching a current density of ~ 10 mA/cm2 at an overpotential of ~ 245mV. Chronoamperometry tests conducted in 1N H2SO4 solution at ~1.5 V (vs NHE) for 24 hours also show marginal loss in current density, indicating good electrochemical stability of the as-prepared electro-catalyst. In summary, we have synthesized highly efficient PGM-free F doped TMN pnictide based electro-catalyst for OER in PEM based water electrolysis. The superior electrocatalytic activity of this electro-catalyst is attributed to the modification of the electronic structure (as evidenced by the theoretical studies) and lower charge transfer resistance (i.e. lower activation polarization). Thus, the present electro-catalyst system is indeed promising and beneficial for the economical and efficient hydrogen production from PEM water splitting. Results of these studies will be presented and discussed.
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