ABSTRACT
The exploitation of functional materials is paramount for the development of renewable energy to alleviate the storage of freshwater and energy. Herein, a series of perovskites, La1-xSrxCoO3 (LSC), were prepared by a facile hydrothermal and calcination method, in which the oxygen evolution reaction (OER) activity was facilitated with the composition of x = 0.1. Moreover, the two-dimensional (2D) Ti3C2 MXene dopant was introduced to boost the functions of electrocatalytic oxygen evolution capability and solar thermal evaporation performance. Strong interfacial interaction and prominent charge-transfer between the La1-xSrxCoO3 and Ti3C2 MXene accelerate the redox process of perovskite La1-xSrxCoO3. The obtained La0.9Sr0.1CoO3/Ti3C2 MXene (LSM) composite acquired an overpotential of 330 mV at 10 mA cm-2 in 1 M KOH electrolyte while maintaining remarkable durability. The lower Tafel slope of 83.9 mV per decade for the OER was also achieved, comparable to that of the commercial RuO2 catalyst. In addition, the LSM exhibited a high solar-evaporation conversion efficiency of 96.8% under 1 sun irradiation, which demonstrated the multi-functionality of this composite. Hence, by presenting high performance in energy conversion of perovskite-derived materials, this work demonstrates their great potential in practical applications for solar driven desalination and highly active electrocatalysis technologies.
ABSTRACT
Effectively harnessing renewable and inexhaustible solar radiation for energy conversion has attracted significant research interest in the past decade. Solar thermal conversion, as a ubiquitous phenomenon, can be implemented to evaporate water and concurrently boost photocatalytic performance for addressing freshwater scarcity and energy crisis. Most recently, solar water evaporation accompanied by photocatalytic degradation, sterilization, and hydrogen production has been proposed as a promising avenue to endow new vitality into the field of clean water and energy production. Driven by the advances of rationally designed solar-powered functional materials, a large variety of photothermal-coupled photocatalysis technologies have been exploited. In this context, it is imperative to summarize the recent progress and discuss the challenges in this multidisciplinary field. Herein, we overview photothermal materials based on various fundamental principles and highlight emerging applications in the areas of solar water evaporation, water purification, and solar-driven energy production. Furthermore, the challenges and perspectives toward both fundamental research and practical applications are also proposed. It is envisioned that this review can provide insightful suggestions to further advance the development of integrated solar thermal driven water evaporation and photocatalytic systems to fulfill concurrent energy conversion and environmental applications.
Subject(s)
Solar Energy , Water Purification , Fresh Water , SunlightABSTRACT
Improving evaporation rate is extremely important to promote the application of solar steam generation in clean water production through seawater desalination. However, the theoretical evaporation rate limit of a normal two-dimensional (2D) photothermal evaporator is only about 1.46 kg m-2 h-1. While 3D evaporators can break the limit, they require much more raw materials. In this work, an effective approach for achieving high-yield solar steam generation via the synergy of 2D nanostructure-embedded all-in-one hybrid hydrogel evaporator and surface patterning is reported. This improved surface-patterned evaporator is able to simultaneously lower the enthalpy of vaporization and induce the Marangoni effect near the evaporation surface, thus delivering a high evaporation rate of 3.62 kg m-2 h-1, which is more than twice the theoretical limit of the normal 2D photothermal evaporator. This hybrid hydrogel offers a cost-effective and energy-efficient pathway to mitigate clean water shortages.
ABSTRACT
Rational design and controllable synthesis of efficient electrocatalysts for water oxidation is of significant importance for the development of promising energy conversion systems, in particular integrated photoelectrochemical water splitting devices. Cobalt oxide (Co3O4) nanostructures with mixed valences (II,III) have been regarded as promising electrocatalysts for the oxygen evolution reaction (OER). They are able to promote catalytic support of OER but with only modest activity. Here, we demonstrate that the OER performance of cubic Co3O4 electrocatalyst is obviously improved when they are anchored on delaminated two-dimensional (2D) Ti3C2 MXene nanosheets. Upon activation the overpotential of the hybrid catalyst delivers 300 mV at a current density of 10 mA cm-2 in basic solutions, which is remarkably lower than those of Ti3C2 MXene and Co3O4 nanocubes. The strong interfacial electrostatic interactions between two components contribute to the exceptional catalytic performance and stability. The enhanced OER activity and facile synthesis make these Co3O4 nanocubes-decorated ultrathin 2D Ti3C2 MXene nanosheets useful for constructing efficient and stable electrodes for high-performance electrochemical water splitting.
