An Efficient and Durable Electrocatalyst for Hydrogen Production Based on Earth-Abundant Oxide-Graphene Composite

Abstract

LaFeO3‐graphene nanostructured composite was synthesized for the first time by a simple, green, low‐cost and one‐pot method using inexpensive instrumentation. The approach is based on using graphene oxide (GO) as an effective oxidizing agent fuel and microwave irradiation for reaction initiation. A well‐defined perovskite structure was obtained without further calcination and the direct reduction of GO to reduced graphene oxide (RGO) was achieved. Hazardous or reducing agents were not used in this procedure. The successful preparation is confirmed by different structural, surface and spectral analyses. The obtained LaFeO3‐RGO was used as an electrode material for hydrogen evolution reaction (HER) in both acidic and basic media. The proposed electrode showed relatively higher kinetic parameters compared to LaFeO3 prepared by microwave‐assisted citrate method. LaFeO3‐RGO showed a current density two orders of magnitude higher than LaFeO3. The overpotential required to reach 10 mA/cm2 is 130 mV for LaFeO3‐RGO compared to 490 mV in case of LaFeO3 prepared by microwave‐assisted citrate method.

Perovskite Oxide Based Electrodes for High‐Performance Photoelectrochemical Water Splitting

“…[77] Perovskite oxides with visible light response such as LaFeO 3 ,d oped LaFeO 3 ,F e-doped SrTiO 3 are demonstrated to show considerable electrocatalytic activity for the HER and OER, which may have possibilities to function as photoelectrodes and cocatalysts simultaneously. [53,54,[83][84][85][86][87][88] Due to the large kinetic barriers of OER in water splitting, researchers mainly focus on the development of highperformance OER electrocatalysts based on visible-lightactive LaFeO 3 perovskite oxide through A-site doping, B-site doping, and the tuning of the cation deficiency. [53,86,87] For example,A -site Sr-doped LaFeO 3 perovskite oxides with various compositions of La 1Àx Sr x FeO 3Àd (x = 0, 0.2, 0.5, 0.8 and 1) were developed as electrocatalysts for the OER.…”

“…More specifically, Pr 0.5 Ba 0.25 Sr 0.25 Co 0.8 Fe 0.2 O 3−δ perovskite is one of the pioneering electrocatalysts for HER in alkaline solution and comparable HER activity as well as superior durability to those of Pt were achieved . Perovskite oxides with visible light response such as LaFeO 3 , doped LaFeO 3 , Fe‐doped SrTiO 3 are demonstrated to show considerable electrocatalytic activity for the HER and OER, which may have possibilities to function as photoelectrodes and cocatalysts simultaneously …”

Porous LaFeO3 nanofiber with oxygen vacancies as an efficient electrocatalyst for N2 conversion to NH3 under ambient conditions

“…An immediate outlook for large-scale indus-trial applications point toward using systems without expensive precious metals, which strongly encourages the development of noble-metal-free NRR electrocatalysts . LaFeO 3 is widely applied in the fields of catalysis, gas sensors and fuel cells, due to their abundance storage in earth, environmental benignity, high stability, and durability [42][43][44] . Recently, researchers find that the oxides with oxygen vacancies (Vo) can adsorb and activate N 2 molecules under ambient conditions [45 , 46] .…”

Perowskitoxid‐Elektroden zur leistungsstarken photoelektrochemischen Wasserspaltung

“…Insbesondere erwies sich der Pr 0.5 Ba 0.25 Sr 0.25 Co 0.8 Fe 0.2 O 3− δ ‐Perowskit als richtungweisender Elektrokatalysator für die HER in alkalischer Lösung, und es wurden eine vergleichbare HER‐Aktivität wie mit Pt sowie eine höhere Beständigkeit erreicht . Für auf sichtbares Licht ansprechende Perowskitoxide wie LaFeO 3 , dotiertes LaFeO 3 und Fe‐dotiertes SrTiO 3 hat man beträchtliche elektrokatalytische Aktivität für die HER und OER nachgewiesen, woraus sich für diese die Möglichkeit ergeben könnte, zugleich als Photoelektroden und Cokatalysatoren zu agieren …”