Harvesting solar energy for desalination and sewage treatment has been considered as a promising solution to produce clean water. However, state-of-the-art technologies often require optical concentrators and complicated systems with multiple components, leading to poor efficiency and high cost. Here, we demonstrate an extremely simple and standalone solar energy converter consisting of only an as-prepared 3D cross-linked honeycomb graphene foam material without any other supporting components. This simple all-in-one material can act as an ideal solar thermal converter capable of capturing and converting sunlight into heat, which in turn can distill water from various water sources into steam and produce purified water under ambient conditions and low solar flux with very high efficiency. High specific water production rate of 2.6 kg h m g was achieved with near ∼87% under 1 sun intensity and >80% efficiency even under ambient sunlight (<1 sun). This scalable sheet-like material was used to obtain pure drinkable water from both seawater and sewage water under ambient conditions. Our results demonstrate a competent monolithic material platform providing a paradigm change in water purification by using a simple, point of use, reusable, and low-cost solar thermal water purification system for a variety of environmental conditions.

Liquid metal (LM) with high electrical conductivity, thermal conductivity, excellent biocompatibility, and extraordinary fluidity has emerged as a promising class of functional materials. However, such materials still encounter many practical challenges due to the rather limited forms available so far. As a promising remedy, LM composites in synergy with other materials would open tremendous opportunities for fundamental research or practical applications. This is because controllable integration of base LM with functional materials (e.g., metal nanoparticles, polymers, and drug molecules) would significantly tune the intrinsic properties of LM as desired, enabling it to offer further major potential in tackling various sectors' challenging issues, including thermal management, biomedicine, chemical catalysis, flexible electronics, and soft robots. Here, we systematically summarize and review the fundamental progress in pursuing LM composites. The basic composite strategies are outlined in three categories: LM composites with core-shell structure, LM-polymer composites, and LM-particle composites. The effectiveness of the composite strategy is illustrated via the typical applications of LM composites in representative fields. The challenges and perspectives in developing LM composites are also identified and interpreted to better guide future research. It is expected that the coming LM era will witness a new world of fruitful composites thereby discovered or invented.

Graphene has been attracting wide interests owing to its excellent electronic, thermal, and mechanical performances. Despite the availability of several production techniques, it is still a great challenge to achieve wafer-size graphene with acceptable uniformity and low cost, which would determine the future of graphene electronics. Here we report a universal segregation growth technique for batch production of high-quality wafer-scale graphene from non-noble metal films. Without any extraneous carbon sources, 4 in. graphene wafers have been obtained from Ni, Co, Cu-Ni alloy, and so forth via thermal annealing with over 82% being 1-3 layers and excellent reproducibility. We demonstrate the first example of monolayer and bilayer graphene wafers using Cu-Ni alloy by combining the distinct segregation behaviors of Cu and Ni. Together with the easy detachment from growth substrates, we believe this facile segregation technique will offer a great driving force for graphene research.