The development of earth-friendly
efficient electrocatalysts for
the oxygen evolution reaction (OER) becomes crucial for renewable
energy production. In this work, green synthesized reduced cobalt
ferrocyanide at different time intervals (RCFC-t)
was demonstrated as an effective and long-lasting electrocatalyst
for the OER process. The RCFC-10 loaded glassy carbon electrode runs
at an overpotential of 321 mV (1.55 V) at 10 mA cm–2, and a lower overpotential of 291 mV exhibited by the optimal RCFC-10/nickel
foam was almost comparable to the benchmark catalyst, such as IrO2. This newborn RCFC-10 shows excellent OER performance and
durability over 250 h with 4.1% potential loss in alkaline medium.
At 1.58 V, the solar-driven water electrolysis demonstration supports
the efficiency of a newborn electrocatalyst in solar-to-hydrogen conversion.
These research findings confirm that low-cost greener synthesized
RCFC-10/NF can be used for large-scale hydrogen generation.
We report a promising synthetic method
for the binder-free synthesis
of a low-cost and efficient solar-driven electrolyzer [Co(OH)2/NF] consisting of earth abundant cobalt metal which can be
employed for hydrogen (and oxygen) generation in 1 M KOH. The direct
growth of Co(OH)2 on nickel foam (NF) [Co(OH)2/NF)] makes this an effective bifunctional catalyst-electrode pair
for water splitting with high activity and excellent stability. The
Co(OH)2/NF electrode exhibits an overpotential of 182 mV
(112 mV dec–1) for hydrogen evolution reaction (HER)
and 281 mV (88 mV dec–1) for oxygen evolution reaction
(OER) to achieve a current density of 10 mA cm–2 (without iR correction). Co(OH)2/NF
displays long-term durability (150 h) with a low potential loss of
3.1 and 3.4% for HER and OER, respectively. The active bifunctional
Co(OH)2/NF-electrode pair assists in constructing a water
electrolyzer that affords 10 mA cm–2@1.66 V. Co(OH)2/NF//Co(OH)2/NF exhibits high stability (over 150
h) with 4.1% potential loss. The earth abundant nonprecious-metal-based
electrode [Co(OH)2/NF] and the solar cell structure afforded
continuous evolution of hydrogen and oxygen (@1.65 V), which can be
projected to allow for low-cost, large-scale hydrogen generation.
Cobalt anchored polyaniline electrocatalysts (Co@PANI) have been synthesized (Co@PANI‐200, Co@PANI‐400, Co@PANI‐600, Co@PANI‐800) and characterised. The electrical conductivity and stability of Co@PANI increased due to the synergistic effect of PANI and cobalt content. PANI prevents aggregation and show strong binding with cobalt ions. The Co@PANI‐600/GC shows low overpotential of 341 mV @ 10 mA cm−2 current density and the Tafel slope of Co@PANI‐600 (39 mV dec−1) was smaller than IrO2 (98 mV dec−1) for OER. The calculated turnover frequency (TOF) of Co@PANI‐600/GC (0.01609 s−1) was ≈8 times higher than IrO2 (0.0014 s−1) at 1.60 V. Furthermore, the Co@PANI‐600/NF electrocatalyst shows an incredibly low overpotential of 251 mV @10 mA cm−2. This new born Co@PANI‐600/NF exhibits durability over 250 h with only 5.1 % potential loss in alkaline medium. Co@PANI‐600 catalyst exhibits excellent OER performances as well as having enough kinetics to solve the sluggish rate of water oxidation. At 1.54 V, the solar driven water electrolysis demonstration supports the efficiency of new born electrocatalyst in solar to hydrogen conversion. These research findings confirm that Co@PANI‐600 can be used for large‐scale hydrogen generation at the lowest possible cost.
Development of eco-friendly efficient dual electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) gaining increased attention for renewable energy production. Here, the greenly synthesized rCoFe-PBA was established as durable and effective bifunctional electrocatalyst for HER and OER process. The rCoFe-PBA coated Nickel foam electrode exhibit overpotential of 311 mV (OER) and 100 mV (HER) @ 10 mA cm À 2 significantly lower than commercial IrO 2 (381 mV) and near to Pt/C (36 mV). The rCoFe-PBA show smaller Tafel slope (OER: 57 mV dec À 1 ) than IrO 2 (78 mV dec À 1 ) and exhibit Tafel slope of 131 mV dec À 1 (HER) which is near to Pt (90 mV dec À 1 ). Turnover frequency (TOF) was estimated as 0.22 s À 1 (OER) and 0.26 s À 1 (HER) was found to be 5 and 10 times higher than IrO 2 catalyst (0.040 s À 1 ) and Pt/C catalyst (0.025 s À 1 ), respectively. For solar water electrolysis, rCoFe-PBA/NF shows overpotential of 411 mV and durability over 180 h in 1.0 m KOH (4.1 % potential loss). The combination of non-precious electrolyzer, rCoFe-PBA with commercial solar cell produced H 2 gas in alkaline water under sunlight. This methodology proves that the greenly synthesized rCoFe-PBA electrolyzer can outperform the precious electrocatalysts, implying that the cost-effective large scale H 2 production without artificial current is possible with commercial solar cells.
Development of eco-friendly dual electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) gaining importance for renewable energy generation. In this study, greenly synthesized Fe-PANI was reported as...
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