| 초록 |
In recent years, because of depleting fossil fuels and environmental concerns, eco-friendly renewable energy conversion technologies from sustainable energy have attracted tremendous attention, such as water splitting, CO2 conversion and fuel cells. Hydrogen (H2) fuels via water splitting process with electrocatalytic and photocatalytic have been widely considered candidates to solve energy and environmental problems, due to their carbon neutral, abundant and sustainable energy sources. However, the half reaction of the oxygen evolution reaction (OER) during water splitting (H2O → 1/2O2 + H2) encounters the bottle-neck of a kinetically sluggish reaction (4OH-→ 2H2O + O2 + 4e-, in base) and high overpotential value (＞ thermodynamic value: 1.23 V), and plays an important role in controlling the conversion efficiency of the whole water splitting system. Up until now, precious metal based oxide materials (RuO2 and IrO2) have been used as the most active catalyst, despite the high cost, poor stability, and scarcity of these metals. Recently, extensive research activities have focused on multi-composite transition metal (Ni, Fe, Co, Mn, etc.) oxides and hydroxides, perovskite and carbon-based materials (graphite, graphene, and carbon nanotubes (CNT) and carbon quantum dots) as candidate catalysts for water splitting. In summary, using a simple two-step hydrothermal method and calcination process, we demonstrated the synthesis of mesoporous NiO/NiFe2O4 multi-composite hollow nanostructure via Ni3[Fe(CN)6]2 PBA nanocube precursors. We confirmed the formation of uniform mesoporous NiO/NiFe2O4 multi-composite hollow NCs with diameters of about 150 ~ 200 nm after calcination from 500 to 700 oC for 1 hour by PXRD, STEM, and HRTEM analysis. |
