The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop highaspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H 2 O 2 ). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy of 26.96 kJ mol -1 capable of producing a thrust of 0.209 ± 0.049 N from 50% [w/w] H 2 O 2 decomposition within a compact reaction chamber of eight Pt-CNT-MMs in series. A n upward trend in the research and use of unmanned underwater vehicles (UUVs), and in particular micro underwater vehicles (MUVs, small UUVS between 1 and 50 cm in length), for exploration of confined spaces such as ship wrecks, submerged oil pipelines, and various military purposes has been observed over recent years. 1À3 The locomotion of these vehicles is typically controlled by propellerbased systems, which are often used for long-endurance missions. 4À6 However, propeller-based systems are usually limited in their ability to perform tight radius turns, burst-driven docking maneuvers, and lowspeed course corrections. ABSTRACT The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial

High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non-enzymatic, amperometric sensing of hydrogen peroxide (H 2 O 2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 µm. Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H 2 O 2 being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 µM. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through-flow at 100 µL s-1 , a sensitivity of 24,300 µA mM-1 cm-2 was achieved based on the frontal projected area (871 µA mM-1 cm-2 based on the nominal microchannel surface area), with a 0.03 µM limit of detection and a linear sensing range of 0.03-500 µM.