Harnessing solar energy for renewable fuel production through artificial photosynthesis offers an ideal solution to the current energy and environmental crises.Among various methods,photoelectrochemical(PEC)water spli...Harnessing solar energy for renewable fuel production through artificial photosynthesis offers an ideal solution to the current energy and environmental crises.Among various methods,photoelectrochemical(PEC)water splitting stands out as a promising approach for direct solar-driven hydrogen production.Enhancing the efficiency and stability of photoelectrodes is a key focus in PEC water-splitting research.Tantalum nitride(Ta_(3)N_(5)),with its suitable band gap and band-edge positions for PEC water splitting,has emerged as a highly promising photoanode material.This review begins by introducing the history and fundamental characteristics of Ta_(3)N_(5),emphasizing both its advantages and challenges.It then explores methods to improve light absorption efficiency,charge separation and transfer efficiency,surface reaction rate,and the stability of Ta_(3)N_(5) photoanodes.Additionally,the review discusses the progress of research on tandem PEC cells incorporating Ta_(3)N_(5) photoanodes.Finally,it looks ahead to future research directions for Ta_(3)N_(5) photoanodes.The strategic approach outlined in this review can also be applied to other photoelectrode materials,providing guidance for their development.展开更多
The application of naive Koutecky-Levich analysis to micro- and nano-particle modified rotating disk electrodes of partially covered and non-planar geometry is critically analysed. Assuming strong overlap of the diffu...The application of naive Koutecky-Levich analysis to micro- and nano-particle modified rotating disk electrodes of partially covered and non-planar geometry is critically analysed. Assuming strong overlap of the diffusion fields of the particles such that transport to the entire surface is time-independent and one-dimensional, the observed voltammetric response reflects an apparent electrochemical rate o constant koapp, equal to the true rate constant ko describing the redox reaction of interest on the surface of the nanoparticles and the ratio,ψ, of the total electroactive surface area to the geometric area of the rotating disk surface. It is demonstrated that Koutecky-Levich analysis is applicable and yields the expected plots of I-1 versus ω-1 where I is the current and ω is the rotation speed but that the values of the electrochemical rate constants inferred are thereof koapp, not ko. Thus, for ψ 〉 1 apparent electrocatalysis might be naively but wrongly inferred whereas for ψ 〈 1 the deduced electrochemical rate constant will be less than ko. Moreover, the effect of ψ on the observed rotating disk electrode voltammograms is significant, signalling the need for care in the overly simplistic application of Koutecky-Levich analysis to modified rotating electrodes, as is commonly applied for example in the analysis of possible oxygen reduction catalysts.展开更多
文摘Harnessing solar energy for renewable fuel production through artificial photosynthesis offers an ideal solution to the current energy and environmental crises.Among various methods,photoelectrochemical(PEC)water splitting stands out as a promising approach for direct solar-driven hydrogen production.Enhancing the efficiency and stability of photoelectrodes is a key focus in PEC water-splitting research.Tantalum nitride(Ta_(3)N_(5)),with its suitable band gap and band-edge positions for PEC water splitting,has emerged as a highly promising photoanode material.This review begins by introducing the history and fundamental characteristics of Ta_(3)N_(5),emphasizing both its advantages and challenges.It then explores methods to improve light absorption efficiency,charge separation and transfer efficiency,surface reaction rate,and the stability of Ta_(3)N_(5) photoanodes.Additionally,the review discusses the progress of research on tandem PEC cells incorporating Ta_(3)N_(5) photoanodes.Finally,it looks ahead to future research directions for Ta_(3)N_(5) photoanodes.The strategic approach outlined in this review can also be applied to other photoelectrode materials,providing guidance for their development.
文摘The application of naive Koutecky-Levich analysis to micro- and nano-particle modified rotating disk electrodes of partially covered and non-planar geometry is critically analysed. Assuming strong overlap of the diffusion fields of the particles such that transport to the entire surface is time-independent and one-dimensional, the observed voltammetric response reflects an apparent electrochemical rate o constant koapp, equal to the true rate constant ko describing the redox reaction of interest on the surface of the nanoparticles and the ratio,ψ, of the total electroactive surface area to the geometric area of the rotating disk surface. It is demonstrated that Koutecky-Levich analysis is applicable and yields the expected plots of I-1 versus ω-1 where I is the current and ω is the rotation speed but that the values of the electrochemical rate constants inferred are thereof koapp, not ko. Thus, for ψ 〉 1 apparent electrocatalysis might be naively but wrongly inferred whereas for ψ 〈 1 the deduced electrochemical rate constant will be less than ko. Moreover, the effect of ψ on the observed rotating disk electrode voltammograms is significant, signalling the need for care in the overly simplistic application of Koutecky-Levich analysis to modified rotating electrodes, as is commonly applied for example in the analysis of possible oxygen reduction catalysts.
