Transforming g-C3N4 from amphoteric to n-type semiconductor: The important role of p/n type on photoelectrochemical cathodic protection

Oxygen vacancy and p–n heterojunction in a g-C3N4 nanosheet/CuFeO2 nanocomposite for enhanced photocatalytic N2 fixation to NH3 under ambient conditions

“…As can be seen, the Mott-Schottky curves exhibit a positive slope for CNns and a negative slope for CFO, indicating that CNns and CFO are typical n-type and p-type semiconductors, respectively. [80][81][82] The corresponding flat band potentials (E fb ) can be calculated according to the following equation: 83…”

“…As can be seen, the Mott–Schottky curves exhibit a positive slope for CNns and a negative slope for CFO, indicating that CNns and CFO are typical n-type and p-type semiconductors, respectively. 80–82 The corresponding flat band potentials ( E fb ) can be calculated according to the following equation: 83 C : depletion layer capacitance; N d : carrier donor density; e : electron charge; ε r : dielectric constant; ε 0 : vacuum permittivity; E : electrode applied potential; E fb : flat band potentials; K : Boltzmann constant; T : temperature; by extrapolation to 1/ C 2 = 0, the E fb for CNns and CFO were obtained at −1.36 V and +0.21 V vs. Ag/AgCl, respectively. The obtained potentials vs. Ag/AgCl can be converted to the potential vs. the normal hydrogen electrode (NHE), which is given as follows: 84 E NHE = E Ag/AgCl + 0.2After converting, the E fb for CNns and CFO are −1.16 V and +0.41 V vs. NHE, respectively.…”

Capturing Solar Energy for Cathodic Protection of Metals: The Life of Photoexcited Charge Carriers

“…The choice of photoanode materials and modulation strategies depends on the functional requirements of PECCP (for example, whether it is carbon steel (CS) or stainless steel (SS) that needs to be protected, and whether hole-trapping agents are to be added). Although various photoactive materials, including metal oxides, carbon-based materials, [43,64,65] and organic polymers, [66] are available for building PECCP systems, a single material can hardly meet all essential requirements due to its limitations in efficiency, stability, CB position, etc. Therefore, the rational design and construction of photoanode in PECCP have been an important research task.…”

“…In contrast, elemental doping including metal doping (Cr, [39,75] Ni, [76] K, [64,77] etc.) as well as non-metal doping (I, [64] N, [78] S, [78] etc.)…”

“…In contrast, elemental doping including metal doping (Cr, [39,75] Ni, [76] K, [64,77] etc.) as well as non-metal doping (I, [64] N, [78] S, [78] etc.) has been demonstrated to be effective for broadening the photoresponse range of semiconductors (such as SrTiO 3 , [39] TiO 2, [75][76][77][78] and C 3 N 4 [64] ) via introducing localized in-gap electronic states (Figure 6).…”