Development of highly efficient, earth-abundant, and cost-effective electrocatalysts for the kinetically sluggish and energy-intensive anodic oxygen evolution reaction (OER) is crucial for realizing the large-scale commercialization of proton exchange membrane based water electrolysis (PEMWE). Herein, we report the results of one-dimensional (1D) nanorods (NRs) containing an ultralow amount of noble metal (iridium, Ir) and 10 wt % fluorine (F) doped (Mn0.8Ir0.2)­O2:10F as an efficient anode electrocatalyst, synthesized via a simple hydrothermal and wet chemical approach for the acidic OER. The as-synthesized (Mn0.8Ir0.2)­O2:10F NRs demonstrate promising electrocatalytic performance for the OER with significantly lower overpotential (η) and higher current density than state of the art IrO2 and many other electrocatalysts containing noble metal/reduced noble metal. Owing to the presence of 1D channels of the nanorod architecture and the unique electronic structure obtained upon formation of an F-containing solid solution, the (Mn0.8Ir0.2)­O2:10F NRs exhibit low charge transfer resistance (∼2.5 Ω cm2), low Tafel slope (∼38 mV dec–1), low water contact angle (∼18°), high electrochemical active surface area (ECSA ≈ 704.76 m2 g–1), high roughness factor (∼2114), and notable OER performance with ∼6-, ∼2.1-, and ∼2.2-fold higher electrocatalytic activity in comparison to IrO2, (Mn0.8Ir0.2)­O2 NRs and a 2D thin film of (Mn0.8Ir0.2)­O2:10F, respectively. The significantly higher ECSA and BET specific activity (0.11 mA cm−2 BET), mass activity (40 Ag–1), and TOF (0.01 s–1) at an overpotential (η) of 220 mV suggest the intrinsically higher catalytic activity of (Mn0.8Ir0.2)­O2:10F NRs in comparison to other as-synthesized electrocatalysts. In addition, (Mn0.8Ir0.2)­O2:10F NRs function as robust electrocatalysts by delivering a current density of 10 mA cm–2 at η ≈ 200 mV and displaying long-term durability, devoid of any degradation of the catalytic activity, suggesting the structural robustness for displaying prolonged OER activity. Herein, on the basis of the synergistic effects of tailoring of 2D material length scales into a 1D nanorod framework and the corresponding formation of an F-substituted unique solid solution structure (as validated by density functional theory), (Mn0.8Ir0.2)­O2:10F NRs offer promise for an efficient OER in PEMWE.

The exploration of high performance electro-catalysts to facilitate oxygen evolution reaction (OER) in proton exchange membrane based water splitting is of vital importance for various energy storage devices and for sustainable hydrogen production.

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.