> ## Content Index > Fetch the complete content index at: https://research-pop.com/llms.txt > Use this file to discover other available public pages before exploring further. # UNSW-led team accelerates water desorption at a liquid-metal-graphene oxide interface for high-rate solar evaporation - URL: https://research-pop.com/unsw-led-team-accelerates-water-desorption-at-a-liquid-metal-graphene-oxide-interface-for-high-rate-solar-evaporation/ - Published: 2026-09-16T12:15:13.000Z - Updated: 2026-09-16T12:15:13.000Z - Author: ResearchPOP ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-16-at-13.49.04.png) **Source**: [https://www.nature.com/articles/s41893-026-01934-4](https://www.nature.com/articles/s41893-026-01934-4?ref=research-pop.com) ## At a glance Solar-driven interfacial evaporation concentrates heat close to the water-air interface, allowing sunlight to produce water vapour without heating an entire body of water. Research in this area has focused on light absorption, photothermal conversion and water transport through the evaporator. A team led by the University of New South Wales investigates another step in the sequence: how quickly water can detach from the photothermal surface and enter the vapour phase. The researchers created a dual-phase photothermal heterostructure from graphene oxide (GO) and eutectic gallium-indium (EGaIn). An amorphous Ga2O3 layer naturally forms on the liquid-metal nanospheres, and its surface Ga3+ sites coordinate with oxygen-containing groups on GO. This interface weakens interactions with water and accelerates desorption. The team then embedded the absorber in a poly(vinyl alcohol) hydrogel with aligned main channels and branched microchannels, producing a GO-EGaIn-PVA hydrogel evaporator called EGH. The 3-mm EGH evaporator reached 3.64 kg m^-2 h^-1 with 95.3% energy efficiency under 1 sun at 30% relative humidity. Increasing its height-to-radius ratio to 4.17 raised the evaporation rate to 7.54 kg m^-2 h^-1 at 96.2% efficiency. The study connects these performance values with molecular-dynamics calculations, in situ spectroscopy, water-state analysis, transport simulations, 30 days of indoor cycling and an outdoor freshwater-collection array. ## Background An interfacial solar evaporator coordinates several processes. It absorbs the solar spectrum, converts light into heat, limits heat loss into bulk water, supplies liquid through its pores, transforms water at the surface and allows vapour to leave before it condenses elsewhere. The overall evaporation rate depends on how these steps work together. Water inside a hydrogel can occupy different states. Strongly bound water interacts closely with polymer chains and contributes little to evaporation. Free water retains a hydrogen-bond network similar to bulk liquid. Intermediate water forms smaller clusters with fewer hydrogen bonds and can be vaporized with less energy. The authors connect these scales in their design. The GO-Ga2O3 interface promotes water release, while the hydrogel channels continuously supply water and increase the fraction assigned to the intermediate state. ## Research question The study examines whether accelerating water desorption from a photothermal surface can increase solar-evaporation rates while maintaining broad light absorption. The researchers establish the structure and chemistry of the GO-EGaIn interface, compare water motion and drying at different surfaces, integrate the interface into a water-supplying hydrogel, and evaluate the resulting evaporator through repeated indoor cycles and outdoor freshwater collection. ## Inside the study ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/image-22.png) The material combines graphene oxide with eutectic gallium-indium nanospheres inside a porous PVA hydrogel. Microscopy and spectroscopy show liquid-metal nanospheres covered by an amorphous gallium-oxide surface, together with interactions between gallium sites and oxygen-containing groups on graphene oxide. The composite absorbs strongly across the solar spectrum. Freeze-drying and cross-linking create aligned channels for capillary water supply and smaller branches that distribute water throughout the evaporating region. The authors connect this architecture with faster water transport at the graphene-oxide/gallium-oxide interface. Molecular-dynamics comparisons give the highest water-mobility measure for the exposed gallium-oxide-on-carbon arrangement. Under illumination, in situ infrared measurements show water-related bands returning to the dry-state baseline faster for the heterostructure than for graphene oxide alone. Raman analysis also identifies a larger intermediate-water fraction in the composite hydrogel. Together, the heterostructure promotes water desorption while the channel network continuously replenishes the surface. Under one-sun illumination at 43% relative humidity, the hydrogel reached an evaporation rate of 2.99 kg m^-2 h^-1 with an energy efficiency of 95.1%. With real seawater, the rate was 2.94 kg m^-2 h^-1\. Lowering the relative humidity to 30% increased the thin-device rate to 3.64 kg m^-2 h^-1\. A high-aspect-ratio configuration produced the maximum reported value of 7.54 kg m^-2 h^-1 at 96.2% efficiency. Repeated-operation and outdoor tests show how the material performs beyond an individual evaporation measurement. During a 30-day indoor light-dark schedule, the illuminated evaporation rate averaged 2.90 kg m^-2 h^-1, while salt deposited during illumination redissolved during dark intervals. In an enclosed outdoor collector using Tasman Sea water, condensed droplets were collected throughout the day, reaching a peak collected-water rate of 1.5 kg m^-2 h^-1 around midday. Concentrations of major seawater ions decreased by approximately two orders of magnitude, and a model organic-dye solution became optically clear after treatment. The outdoor system was operated for 60 days. On day 50, it produced 12.4 L m^-2 of water over 10 daytime hours, corresponding to a water-collection-to-solar-input ratio of 4.35 g W^-1 h^-1\. These experiments connect photothermal evaporation with condensation and freshwater collection in an integrated device. ## Takeaways and outlook The study connects interface chemistry with water transport and collection. The GO-amorphous-Ga2O3 contact retains broad solar absorption while changing the environment experienced by surface water. Molecular simulations and in situ infrared spectroscopy describe faster desorption, while the hydrogel channels maintain water supply and favour the intermediate-water state. The insulated geometry retains heat near the evaporation zone, and the light-dark operating cycle allows deposited salt to redissolve. The authors present interfacial desorption management as a broader design strategy for solar evaporation. By coordinating water movement through pores, hydrogen-bond states, a desorbing interface and a condenser, the system treats water transport as one connected pathway. Future development focuses on lower-cost photothermal heterostructures and collectors that convert more of the generated vapour into usable freshwater. ## About the researchers Tao Yin (University of New South Wales) is the first author. Tao Wan (University of New South Wales), Jianbo Tang (Westlake University), Yunjian Liu (Jiangsu University) and Dewei Chu (University of New South Wales) are the corresponding authors. The other authors are Ziheng Feng, Mengyao Li, Chao Liu, Jinbo Wang, Fandi Chen, Jiajun Fan, Long Hu, Tao Cao and Zhi Li (University of New South Wales); Dawei Su (RMIT University); Zhaojun Han (Eastern Institute of Technology, Ningbo); Haolan Xu (University of South Australia); and Qin Li (Griffith University). ## Original research Tao Yin; Tao Wan; Ziheng Feng; Mengyao Li; Chao Liu; Jinbo Wang; Fandi Chen; Jiajun Fan; Long Hu; Tao Cao; Dawei Su; Jianbo Tang; Zhaojun Han; Zhi Li; Yunjian Liu; Haolan Xu; Qin Li; Dewei Chu. Accelerating water desorption at heterostructure interfaces for high-rate solar evaporation. *Nature Sustainability* (2026). Published online 15 September 2026\. DOI: 10.1038/s41893-026-01934-4. --- ## Research POP Notes This article reflects the independent interpretation of the Research POP team and does not represent the views of the authors, their institutions or the journal. If you identify any inaccuracies or have concerns regarding the content, figures or attribution, please contact us at [team.researchpop@gmail.com](mailto:team.researchpop@gmail.com). We will review the matter promptly and make corrections or remove the relevant material where appropriate.