December 27, 2017

Researchers at Columbia University have developed the first demonstration of a practical, floating, membrane-free and pump-free photovoltaic-driven electrolysis device. The device consists of platforms of solar-powered electrolyzers floating on the sea to generate hydrogen fuel. It uses electrodes made of sheets of titanium mesh suspended in water. A platinum catalyst coats just one side of each sheet. When a mesh electrode is negatively charged, hydrogen bubbles develop on the side coated with the catalyst. The mesh electrodes are each placed at diagonal angles in the water. When the bubbles of gas grow large enough, their buoyancy makes them detach from the mesh and float upward unimpeded. On one configuration, hydrogen bubbles can float into one set o chambers and oxygen into a separate array that vents it out into the atmosphere. This simple design requires relatively few parts that should lower the materials and assembly costs. Future work could refine the design for more efficient operation in seawater.

Based of buoyancy-induced separation, the simple electrolyzer design produces hydrogen up to 99% pure. This simple design, without membrane or pumps, makes it particularly attractive for its application to seawater electrolysis.

This design is ideally suited for protected, natural bodies of sea water such as Mexico’s Sea of Cortez and Turkey’s Sea of Marmara and artificial that could be created by flooding natural below-sea-level depressions such Death Valley and neighboring dry lake beds, the Dead Sea, the Qattara Depression in Egypt, and the Laguna del Carbón in Argentina. As a bonus, flooding these vast areas would mitigate rising seas threatening low-lying coastal cities worldwide.