Efficient sequential harvesting of solar light by heterogeneous hollow shells with hierarchical pores

Abstract

In nature, sequential harvesting of light widely exists in the old life entity, i.e. cyanobacteria, to maximize the light absorption and enhance the photosynthesis efficiency. Inspired by nature, we propose a brand new concept of temporally-spatially sequential harvesting of light in one single particle, which has purpose-designed heterogeneous hollow multi-shelled structures (HoMSs) with porous shells composed of nanoparticle subunits. Structurally, HoMSs consist of different band-gap materials outside-in, thus realizing the efficient harvesting of light with different wavelengths. Moreover, introducing oxygen vacancies into each nanoparticle subunit can also enhance the light absorption. With the benefit of sequential harvesting of light in HoMSs, the quantum efficiency at wavelength of 400 nm is enhanced by six times compared with the corresponding nanoparticles. Impressively, using these aforementioned materials as photocatalysts, highly efficient photocatalytic water splitting is realized, which cannot be achieved by using the nanoparticle counterparts. This new concept of temporally-spatially sequential harvesting of solar light paves the way for solving the ever-growing energy demand.

Nature and Chinese Art Inspire Materials for Light Harvesting

“…10 Recent work demonstrated a major advancement in HoMSs, which exploits a temporally spatially ordered design. 11 Inspired by the antenna system of cyanobacteria in nature, it is possible to engineer the bandgap in single HoMSs, thereby sequentially harvesting solar radiation and absorbing a larger portion of the spectrum. Specifically, a variation of the traditional sequential templating approach (STA) was developed to fabricate different HoMSs with tunable structures, compositions, and surface properties.…”

“…The advance, reported by Wang and co-authors, adds a spatial dimension that creates a band-gap gradient in the shells. 11 Starting with a carbon microsphere (CMS) template and by ingeniously choosing appropriate metal ions (i.e., their charge, size, and concentration), they regulated the amount and distribution of Ti + and Cu + ions absorbed in the CMS templates. The latter are removed by controlled annealing, yielding TiO 2 -Cu x O HoMSs with size in the 600-800 nm range.…”

“…To further assert the versatility of the STA approach, the authors also prepared HoMSs based on CeO 2 -CeFeO 3 , a nontoxic, inexpensive, rare earth material with versatile and robust catalytic properties, following a similar procedure. 11 In this case, sequential light absorption was obtained by accurate control of the oxygen vacancies on the surface of the zero-dimensional (0D) nanocrystals that make up the hollow shells. The optimized CeO 2 -CeFeO 3 HoMSs, in the presence of an electron scavenger, showed a remarkable activity for the oxygen evolution reaction (OER), with maximum value of 452 mmol/h.…”

When hollow multishelled structures (HoMSs) meet metal–organic frameworks (MOFs)

“…The hetero-HoMSs can successively absorb sunlight with different wavelengths in different shells from outside to inside (sequential solar-light-harvesting), broadening the absorption range of solar spectrum and enhancing the utilization of light. 77 (2) For HoMS-MOFs, besides the shell-by-shell approach, there is still an urgent need for new methods. For example, we can predict that the solid HoMS could also be considered as a precursor and a template to direct the HoMS-MOF formation.…”

Steering Hollow Multishelled Structures in Photocatalysis: Optimizing Surface and Mass Transport

“…[30,31] One step further, constructing HoMSs with heterogeneous compositions inside out would endow it with sequential light absorption as the nature does. [32,33] Till now, although research efforts on the design of HoMSs materials for photocatalytic applications have been intensively made, [34][35][36][37][38][39][40][41][42][43][44][45][46][47] the impacts of physi-chemical properties of HoMSs on the specific kinetic or energetic bottlenecks in photocatalytic processes have not been comprehensively summarized, which are critically important for further evolvement of efficient HoMSs photocatalysts. In this review, we first briefly introduce the fabrication process, especially the sequential templating approach, followed by discussing the two key parameters for enhancing the photocatalytic performance in optimizing the mass transport and effective surface area, then highlighted rational design for improving the photocatalytic and the applications of HoMSs materials in photocatalysis are enumerated throughout to reveal the research tendency of HoMSs photocatalysts.…”