Qi Wang,Lanlan Zhang,Yuhong He,Zonghan Hu,Yangfang Liao,Qingping Dai,Bing Lv,Wenzhong Wang
Rational design and construction of semiconductor heterojunction photoelectrode can effectively improve photoelectrochemical (PEC) water splitting for hydrogen evolution . In this study, for the first time, a novel n-type Fe 2 V 4 O 13 (FVO) nanoparticle-modified p-type CuInS 2 (CIS) nanosheet arrays (NSAs) photocathode is designed and constructed for hydrogen evolution through PEC cell . The CIS/FVO NSAs photocathode simultaneously with type II heterojunction and p-n junction was constructed by growing FVO nanoparticles (NPs) on CIS NSAs through a facile successive ionic layer adsorption and reaction (SILAR) as well as annealing method. The designed and constructed CIS/FVO NSAs photocathode exhibited drastically improved PEC water splitting for hydrogen evolution and generated a photocurrent of −4.8 mA/cm 2 , 9.5 times that of pristine CIS NSAs photocathode at −1.0 V vs. Ag/AgCl. UV–vis absorption spectrum tests demonstrated the outstanding light absorption of CIS/FVO NSAs within the wavelength of 300–800 nm. Electrochemical impedance and photoluminescence measurements evidenced the effective separation of the carriers within the CIS/FVO NSAs. Mott-Schottky tests confirmed the establishment of type II heterojunction between the interface of p-type CIS and n-type FVO. The experimental tests revealed that the enhanced PEC water splitting performance of the CIS/FVO NSAs photocathode is attributed to the outstanding light absorption and the effective charge carrier separation achieved by type II heterojunction and p-n junction. This work provides a new strategy to design and construct CIS-based photocathode for highly efficient PEC water splitting hydrogen evolution.
Bing Lv,Qi Wang,Yuhong He,Lanlan Zhang,Wenzhong Wang
In this study, we demonstrate for the first time a promising photoanode of Fe 2 V 4 O 13 /In 2 S 3 (FVO/IS) nanoparticles (NPs) for photoelectrochemical (PEC) water splitting. Most importantly, this work presents the first application of X-ray photoelectron spectroscopy in tracking electron flow direction within FVO/IS to reveal the formation of heterojunction having the electron flow from IS to FVO. Mott-Schottky measurement confirms that the modification of IS NPs establishes the type II heterojunction between FVO and IS, favorable for the transport and separation of carriers. Spectral measurements of electrochemical impedance spectroscopy , photoluminescence and Bode diagram confirm the effective separation of carriers and the prolongation of the charge lifetime in the FVO/IS heterojunction photoanode. Moreover, the electrochemical measurements evidently demonstrate the substantial enhancement in the charge separation efficiency ( η separation ) and charge transfer efficiency ( η transfer ) of the photoanode, leading to significantly enhanced PEC water splitting capability. As a result, in contrast with the pure FVO NPs photoanode, the photocurrent density of the constructed FVO/IS NPs photoanode is increased by 27 times without bias. This study paves a new approach for boosting the PEC water splitting activity of FVO photoanodes by constructing heterostructures through modification with other semiconductors.
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