Multifunctional Coatings from Scalable Single Source Precursor Chemistry in Tandem Photoelectrochemical Water Splitting

Abstract

The straightforward and inexpensive fabrication of stabilized and activated photoelectrodes for application to tandem photoelectrochemical (PEC) water splitting is reported. Semiconductors such as Si, WO3, and BiVO4 can be coated with a composite layer formed upon hydrolytic decomposition of hetero­bimetallic single source precursors (SSPs) based on Ti and Ni, or Ti and Co in a simple single‐step process under ambient conditions. The resulting 3d‐transition metal oxide composite films are multifunctional, as they protect the semiconductor electrode from corrosion with an amorphous TiO2 coating and act as bifunctional electrocatalysts for H2 and O2 evolution based on catalytic Ni or Co species. Thus, this approach enables the use of the same precursors for both photoelectrodes in tandem PEC water splitting, and SSP chemistry is thereby established as a highly versatile low‐cost approach to protect and activate photoelectrodes. In an optimized system, SSP coating of a Si photocathode and a BiVO4 photoanode resulted in a benchmark noble metal‐free dual‐photoelectrode tandem PEC cell for overall solar water splitting with an applied bias solar‐to‐hydrogen conversion efficiency of 0.59% and a half‐life photostability of 5 h.

Enhancing Light Absorption and Charge Transfer Efficiency in Carbon Dots through Graphitization and Core Nitrogen Doping

“…[17] 15 NNMR spectroscopy ( Figure S6) revealed the complete loss of the 15 N(amine) peak in Asp at d = 30.7 ppm along with the formation of as et of sp 2 Np eaks in the range d = 105-120 ppm. [18] Correlations are also observed between 13 Ce nvironments at 172-175 ppm and 15 Nenvironments in the range 108-115 ppm, which may correspond to pyridinic environments.I na greement, the deconvoluted N1s XPS spectrum consists of two peaks at 398.8 and 399.8 eV,which is consistent with previous assignments as pyridinic and pyrrolic nitrogen environments in carbon materials,r espectively (Figure 1c). [18,19] Further,2 D 13 C-15 N correlation NMR (HMQC) experiments ( Figure S6) show direct bonding between nitrogen and core graphitic carbon environments in g-N-CD.Acorrelation is observed between al ower shift sp 21 3 Cs ignal at 129 ppm and a 15 Ns ignal at 107 ppm, which can be assigned as ap yrrolic graphite defect.…”

“…[10,11] This has asignificant impact on the photoluminescence properties of such dots where the fluorescence quantum yields are many times higher than carboxylic acid terminated CDs. [12,13] This work makes use of as ingle-source precursor (SSP) approach, [14,15] where features of the molecule are preserved after decomposition to the forming CD.T he SSP approach allowed us to study the effect of CD graphitization and core doping on photocatalytic fuel formation for the first time. [12,13] This work makes use of as ingle-source precursor (SSP) approach, [14,15] where features of the molecule are preserved after decomposition to the forming CD.T he SSP approach allowed us to study the effect of CD graphitization and core doping on photocatalytic fuel formation for the first time.…”

Solar H2 evolution in water with modified diketopyrrolopyrrole dyes immobilised on molecular Co and Ni catalyst–TiO2 hybrids

“…1–3 Dye-sensitised photocatalysis (DSP) has emerged as a functional bio-inspired approach for sunlight-driven H 2 evolution in water by means of co-immobilising a dye and a catalyst on a semiconductor in suspension (Fig. 1a–c), 4 and this approach can also be adopted in dye-sensitised photoelectrosynthesis cells.…”

Enhancing Light Absorption and Charge Transfer Efficiency in Carbon Dots through Graphitization and Core Nitrogen Doping

“…[3,7,11] Core nitrogen doping of aC D, on the other hand, could have significant effects in the context of photocatalysis through engineering of energy levels or enhancing the efficiency of charge transfer reactions. [12,13] This work makes use of as ingle-source precursor (SSP) approach, [14,15] where features of the molecule are preserved after decomposition to the forming CD.T he SSP approach allowed us to study the effect of CD graphitization and core doping on photocatalytic fuel formation for the first time. Aspartic acid (Asp), alow-cost and naturally abundant amino acid, was utilized as SSP for this purpose ( Figure S1 in the Supporting Information).…”