Recent advances in surface regulation and engineering strategies of photoelectrodes toward enhanced photoelectrochemical water splitting

Recent advances on three-dimensional ordered macroporous metal oxide-based photoelectrodes for photoelectrochemical water splitting

“…42 In addition to the mentioned approaches, decoration of metal oxides with functional materials like organic polymers and metal-organic frameworks (MOFs) can equally facilitate the charge transport and separation. 43 Photocorrosion is also related to the charge transport and transfer process, leading to reduction/oxidation of electrodes, resulting in PEC performance degradation. 36 To tackle this problem, a typical example is to protect the semiconductor electrode with a passivation layer.…”

Using hollow dodecahedral NiCo-LDH with multi-active sites to modify BiVO 4 photoanode facilitates the photoelectrochemical water splitting performance

“…However, given challenges such as slow water oxidation kinetics and severe charge recombination, the actual photocurrent density of BiVO 4 remains considerably lower to its theoretical value (7.5 mA/cm 2 ) [20]. In the pursuit of PEC performance of BiVO 4 enhancement, researchers have developed diverse solution strategies, including morphology control [21][22][23], defect engineering [24][25][26][27], metal doping [28,29], heterostructure construction [15,30,31], and cocatalyst loading [32,33]. For instance, Chang et al create a Co 3 O 4 /BiVO 4 pn heterojunction to improve the PEC performance by enhancing charge transport and separation through the built-in electric field [15].…”

Precise Lattice‐Strain Modulation of Hematite Enabled by Gradient Doping of Mn for Enhanced Photoelectrocatalytic Oxidative C─C Bond Scission

“…Photochemistry (PC) and electrochemistry (EC) have been utilized to investigate C─C bond breaking as clean and sustainable methods. Highly selective cleavage of C─C bonds by active species at metal‐based electrodes in electrochemical catalysis results from the formation of metal oxide/hydroxide/hydroxylated species [ 13,14 ] The activation of free radicals to attack and break the C─C bond is the main mechanism for photochemically selective bond breaking [ 15,16 ] The high energy of C─H dissociation has led to the conclusion that C─H bond activation controls the C─C bond cleavage in the oxidation process [ 17–20 ] Also, the PEC cell, a technology that combines the strengths of PC and EC, has recently been explored in the field of C─H activation for the synthesis of organic small molecules (e.g., H 2 and phenol) [ 21–24 ] In 1972, Honda and Fujishima exhibited the initial use of PEC in the process of water splitting [ 25 ] Several semiconductors such as WO 3 , Fe 2 O 3 , BiVO 4 , and CdS have been used in PEC systems [ 26–33 ] Surface engineering, interface engineering, and bulk engineering techniques have been utilized to enhance the PEC performances of semiconductor photoelectrodes, attributed to the semiconductor bandgap, light absorption range, and self‐limiting nature [ 34–39 ] The modulation of the electronic structure significantly influences the reactivity of the electrodes [ 40,41 ] The d ‐band center theory of electrode structure (i.e., the movement of the d ‐band center) can change the adsorption/desorption capacity of the electrode toward the reaction substrates and its intermediates [ 42,43 ] Shen et al achieved modulation of the d ‐band center by constructing a heterojunction to optimize the electronic structure of Co through charge transfer at the interface, resulting in weak adsorption of * H at the electrode [ 44 ] Hu et al quantitatively investigated the size dependence of the activity using d ‐band centers by controlling the size of Ru nanocrystals on the electrode surface [ 45 ] For bulk engineering, doping can lead to a lattice distortion‐induced lattice strain effect in native phase crystals. The lattice strain effect has also been shown to be used to modulate the adsorption/desorption capacity between substrates and catalyst surfaces, which has become a common strategy for improving electrode performance.…”