John L. Haan

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This article introduces an on-demand microfluidic hydrogen generator that can be integrated with a microproton exchange membrane (PEM) fuel cell. The catalytic reaction, reactant circulation, gas/liquid separation, and autonomous control functionalities are all integrated into a single microfluidic device. It generates hydrated hydrogen gas from an aqueous(More)
Lowering the overpotential for the electrochemical conversion of CO2 to useful products is one of the grand challenges in the Department Of Energy report, “Catalysis for Energy”. In a previous paper, we showed that CO2 conversion occurs at low overpotential on a 1-ethyl-3methylimidazolium tetrafluoroborate (EMIM-BF4)-coated silver catalyst in an aqueous(More)
Paper-based microfluidic fuel cells (MFCs) are a potential replacement for traditional FCs and batteries due to their low cost, portability, and simplicity to operate. In MFCs, separate solutions of fuel and oxidant migrate through paper due to capillary action and laminar flow and, upon contact with each other and catalyst, produce electricity. In the(More)
We describe the first direct formate fuel cell on a paper microfluidic platform. In traditional membrane-less microfluidic fuel cells (MFCs), external pumping consumes power produced by the fuel cell in order to maintain co-laminar flow of the anode stream and oxidant stream to prevent mixing. However, in paper microfluidics, capillary action drives flow(More)
Polymer vesicles are being extensively studied to emulate self-assembly in biological systems and also use them in a variety of biological and industrial applications. This study demonstrates a novel strategy to prepare polymer vesicles in a pure aqueous medium by driving the micelle-to-vesicle transition with metallic nanoparticles. We synthesized(More)
We demonstrate the first device to our knowledge that uses a solar panel to power the electrochemical reduction of dissolved carbon dioxide (carbonate) into formate that is then used in the same device to operate a direct formate fuel cell (DFFC). The electrochemical reduction of carbonate is carried out on a Sn electrode in a reservoir that maintains a(More)
Fabric-based microfluidic fuel cells (MFCs) serve as a novel, cost-efficient alternative to traditional FCs and batteries, since fluids naturally travel across fabric via capillary action, eliminating the need for an external pump and lowering production and operation costs. Building on previous research with Y-shaped paper-based MFCs, fabric-based MFCs(More)
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