Regulation of Ferroelectric Polarization to Achieve Efficient Charge Separation and Transfer in Particulate RuO₂/BiFeO₃ for High Photocatalytic Water Oxidation Activity

Abstract

Exploiting spontaneous polarization of ferroelectric materials to achieve high charge separation efficiency is an intriguing but challenging research topic in solar energy conversion. This work shows that loading high work function RuO2 cocatalyst on BiFeO3 (BFO) nanoparticles enhances the intrinsic ferroelectric polarization by efficient screening of charges to RuO2 via RuO2/BFO heterojunction. This leads to enhancement of the surface photovoltage of RuO2/BFO single nanoparticles nearly 3 times, the driving force for charge separation and transfer in photocatalytic reactions. Consequently, efficient photocatalytic water oxidation is achieved with quantum efficiency as high as 5.36 % at 560 nm, the highest activity reported so far for ferroelectric materials. This work demonstrates that, unlike low photocurrent density in film‐based ferroelectric devices, high photocatalytic activity could be achieved by regulating the ferroelectric spontaneous polarization using appropriate cocatalyst to enhance driving force for efficient separation and transfer of photogenerated charges in particulate ferroelectric semiconductor materials.

Ferroelectric Modulation of Surface Electronic States in BaTiO3 for Enhanced Hydrogen Evolution Activity

“…Ferroelectric perovskites have also been an interesting class of nanomaterials for photocatalysis, since their internal electric field can be used to enhance electron–hole separation. ,− As a recent example, improved photocatalytic oxygen evolution activity has been reported using both bare ferroelectric (e.g., BaTiO 3 , BiFeO 3 , ) films and ferroelectric-supported catalysts, such as RuO 2 /BiFeO 3 . In these studies the heterostructure was used as a photoanode, where ferroelectric polarization enhanced the accumulation of photogenerated holes near the surface to facilitate water oxidation.…”

Synergistic defect- and interfacial-engineering of a Bi2S3-based nanoplate network for high-performance photoelectrochemical solar water splitting

“…Noble metal compounds such as RuO 2 have been initially used as the ideal anodic photocatalysts because of their excellent OER activity but are still limited due to their ultrahigh production cost. [3][4][5] The earth-abundant and non-precious metal oxides such as TiO 2 , WO 3 , a-Fe 2 O 3 , BiVO 4 , etc. are also widely studied for the anode materials.…”

Ferroelectrics in Photocatalysis

“…Shah et al fabricated RuO 2 /BiFeO 3 heterojunction (Figure 7a and b), on which loading the RuO 2 cocatalyst with a high work function on BiFeO 3 nanoparticles enhanced the intrinsic polarization by efficient screening of charges to RuO 2 in RuO 2 /BFO heterojunction (Figure 7c). [56] The enhancement of ferroelectric properties of RuO 2 /BFO was attributed to the synergy of internal electric field of BFO for the primary separation of photogenerated charges and further regulation of separated charges to RuO 2 by the interfacial electric field generated by RuO 2 /BFO heterojunction, which provided synergetic effect to photocatalytic OER with achieving a quantum efficiency as high as 5.36 % at 560 nm. Utilizing the polar nature of ferroelectrics to develop composite semiconductors can form uniform hybrid structure to facilitate spatial distribution of active sites.…”