An integrated photoanode based on non-critical raw materials for robust solar water splitting

Abstract

<p>Herein, we have developed an integrated photoanode for solar water splitting based on an “Earth-abundant” Ni-Fe based electrocatalyst combined with a versatile multijunction Si-based photovoltaic device, designed in such a...</p>

Prediction of Limits of Solar‐to‐Hydrogen Efficiency from Polarization Curves of the Electrochemical Cells

“…At the cell level, the freedom for multijunction cells exists, [7,11,18,31,43,45,53,56] and at the module level, discrete adjustments of the number of cells [6,12,21,23] or modules [54,57] in series, together with an optional serial connection of the EC cells, [14,27,39,54] result in a dense grid of possible combinations that very closely approaches maximum efficiency. At the same time, adjustments of the A EC /A PV ratio [4,13,28,32,[38][39][40][41][42] or adjustments on the side of the EC cell [28,31,34,51,52,58] can be used for fine tuning of the power coupling in solar water-splitting systems. Finally, classical MPP tracker solutions allow the PV device to slide along the I MPP (V MPP ) dependence with a high degree of freedom.…”

“…Making a PV device with a specific position of the maximum point may be challenging in practice for directly integrated systems. At the cell level, the freedom for multijunction cells exists, [ 7,11,18,31,43,45,53,56 ] and at the module level, discrete adjustments of the number of cells [ 6,12,21,23 ] or modules [ 54,57 ] in series, together with an optional serial connection of the EC cells, [ 14,27,39,54 ] result in a dense grid of possible combinations that very closely approaches maximum efficiency. At the same time, adjustments of the A EC / A PV ratio [ 4,13,28,32,38–42 ] or adjustments on the side of the EC cell [ 28,31,34,51,52,58 ] can be used for fine tuning of the power coupling in solar water‐splitting systems.…”

“…Equation (4) describes the voltage efficiency of an EC cell with a Faradaic efficiency of 100%, which is realistic for optimized experimental EC cells. [8,47,48] Although details of the hydrogen and oxygen evolution reactions during water splitting are still under debate, [2,49] we have assumed ΔE ¼ 1.23 V, which is widely used in the literature, [1,[6][7][8][9][10][11][19][20][21][22][23][31][32][33][34][35][43][44][45][46][47][48][50][51][52][53][54][55] to calculate the EC voltage efficiency. In this section, we address the coupling and STH limit problems using the absolute currents of both PV and EC devices as well as the absolute total irradiance P in , which is practical if both devices have predefined areas.…”

“…Both coupling and scaling are crucial inter-related issues for the minimization of energy losses in the PV-EC system and increasing its STH. Many studies have examined the coupling of various PV and EC devices, [4,10,14,16,18,22,23,[26][27][28][29][30][31][32][33][34][35][36][37] their mutual scaling, [4,13,28,32,[38][39][40][41][42] and the limits of STH. [11,21,[43][44][45] In most cases, PV and EC devices are developed separately and then merged at a later stage.…”

Pencil graphite rods decorated with nickel and nickel–iron as low-cost oxygen evolution reaction electrodes

“…solar or wind power. 4 For an efficient energy conversion, the overpotentials needed to drive the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) must be minimized. From a thermodynamic and kinetic point of view, the OER is the limiting reaction as it involves four electrons and a larger overpotential.…”