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NiO Nanoparticles Anchored on Phosphorus‐Doped α‐Fe 2 O 3 Nanoarrays: An Efficient Hole Extraction p–n Heterojunction Photoanode for Water Oxidation
Author(s) -
Li Feng,
Li Jing,
Zhang Jie,
Gao Lili,
Long Xuefeng,
Hu Yiping,
Li Shuwen,
Jin Jun,
Ma Jiantai
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201800571
Subject(s) - non blocking i/o , photocurrent , materials science , heterojunction , water splitting , reversible hydrogen electrode , chemical engineering , doping , nanorod , nanoparticle , hematite , nanotechnology , electrode , electrochemistry , catalysis , optoelectronics , photocatalysis , chemistry , working electrode , metallurgy , biochemistry , engineering
The photoelectrochemical (PEC) water‐splitting efficiency of a hematite‐based photoanode is still far from the theoretical value due to its poor surface reaction kinetics and high density of surface trapping states. To solve these drawbacks, a photoanode consisting of NiO nanoparticles anchored on a gradient phosphorus‐doped α‐Fe 2 O 3 nanorod (NR) array (NiO/P‐α‐Fe 2 O 3 ) was fabricated to achieve optimal light absorption and charge separation, as well as rapid surface reaction kinetics. Specifically, a photoanode with the NR array structure allowed a high mass‐transport rate to be achieved, while phosphorus doping effectively decreased the number of surface trapping sites and improved the electrical conductivity of α‐Fe 2 O 3 . Furthermore, the p–n junction that forms between NiO and P‐α‐Fe 2 O 3 can further improve the PEC performance due to efficient hole extraction and the water oxidization catalytic activity of NiO. Consequently, the NiO/P‐α‐Fe 2 O 3 NR photoanode produced a high photocurrent density of 2.08 mA cm −2 at 1.23 V versus a reversible hydrogen electrode and a 110 mV cathodic shift of the onset potential. This rational design of structure offers a new perspective in exploring high‐performance PEC photoanodes.