Solar water oxidation reaction promoted by a dopant combination on hematite photoanode

Autor(es)

Dotta, Mariana A. ; Pires, Fabio A. ; Morishita, Gustavo M. ; Costa, Carlos A. R. ; Bettini, Jefferson ; Souza, Flavio L.

• Tipo de documento: Artigo Científico
• Fonte: SUSTAINABLE ENERGY & FUELS; v. N/A, p. 19-pg., 2024-11-07.

Resumo

Doping is a widely used strategy to enhance hematite photoelectrochemical performance, but a rational consideration on how to combine positive effects of dopants in dual-modified nanostructures is necessary to achieve materials with controlled properties for different technological applications. Here, a polymeric precursor solution method that simultaneously induces bulk doping and interfacial segregation by adding modifiers in different synthesis stages was used in the search of an ideal couple of dopants toward highly efficient hematite photoanodes. Employing optimized concentrations of bulk dopants (Al3+, Ga3+, Y3+, La3+) and interfacial modifiers (Nb5+, Ta5+), the most synergistic enhancement of photoelectrochemical performance was observed when Y3+ and Ta5+ were combined. The photoanode modified with optimal concentrations of these dopants achieved a total yield of 56.6% of current generated in relation to the maximum value permitted by its absorption properties, remarking a 6-fold increase when compared to pristine hematite (9.9%). Hence, yttrium and tantalum beneficially acted to minimize small polaron domain that prevent electron mobility intragrain, and to increase charge separation efficiency by decreasing the interfacial energies hindering electron hopping trough the grains, respectively. However, the combination of Ga3+ and Nb5+ led to a material with 21.4% of current yield, value comparable to the niobium single-modified photoanode (22.2%), indicating the lack of synergy between these modifiers to address bulk and interfacial issues of hematite. Therefore, this work shows that only chemically compatible combinations of modifiers can deliver efficient hematite-based photoanodes and careful nanostructure engineering must drive the search for an ideal material. (AU)

• Processo FAPESP: 23/08273-8 - Engenharia de interfaces em fotoanodos nanoestruturados de hematita produzidos pelo método de solução precursora polimérica para quebra da molécula da água assistida pela luz solar
• Beneficiário: Fabio Augusto Pires
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 17/11986-5 - Geração e Armazenamento de Novas Energias: trazendo desenvolvimento tecnológico para o país
• Beneficiário: Ana Flávia Nogueira
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia