Electrochemical processes have attracted much attention as they can be empowered by renewable electricity for zero-emission processes under ambient conditions. Applications of electrochemistry in various areas such as electrocatalysis (e.g., water electrolysis, CO₂ reduction), (waste)water treatment, fuel cells, and microbial processes have been recently emerging. Electrode design is a crucial feature in electrochemical systems. In some applications, porous electrodes are required to maximize the reaction sites and participate in reactants delivery, such as gas-diffusion electrodes (GDEs) for gas-phase electrolysis or membrane electrodes for water treatment. Planar shape porous electrodes are the conventional configuration with some drawbacks; for example, planar GDEs are made in multiple layers and are relatively complex to manufacture on large scales. Recently, microtubular (or hollow fiber) shape electrodes have been introduced as an alternative due to several advantages such as a higher active surface area to the volume ratio, small electrolyzer footprint, ease of processability, etc. This review presents a critical overview of the design and fabrication of microtubular electrodes and the structure-performance relationship. After that, the recent advances of microtubular electrodes in three main categories, including gas-phase electrocatalysis, (waste)water treatment, and bioelectrochemical systems, are discussed, with more focus on gas electrolysis wherein microtubular electrodes act as GDEs. GDEs for gas electrocatalysis are of great significance as they effectively boost reaction rate by continuously delivering reactant feeds to the reaction sites, resolving the issue of mass transport resistance, and microtubular GDEs can address several issues of planar GDEs. In the last section, future research opportunities are suggested to showcase the promises of microtubular electrodes as a versatile electrode configuration for electrochemical applications.

电化学过程引起了很多关注，因为它们可以通过可再生电力在环境条件下实现零排放过程。电化学在电催化等各个领域的应用（如水电解、CO ₂减少）、（废水）水处理、燃料电池和微生物过程最近已经出现。电极设计是电化学系统的关键特征。在某些应用中，需要多孔电极来最大化反应位点并参与反应物输送，例如用于气相电解的气体扩散电极 (GDE) 或用于水处理的膜电极。平面形状的多孔电极是具有一些缺点的常规配置；例如，平面 GDE 由多层制成，大规模制造相对复杂。最近，微管（或中空纤维）形状的电极已被引入作为替代品，因为它具有几个优点，例如更高的活性表面积与体积比、小的电解槽占地面积、易于加工等。本综述对微管电极的设计和制造以及结构-性能关系进行了批判性概述。之后，讨论了微管电极在三个主要类别中的最新进展，包括气相电催化、（废水）水处理和生物电化学系统，更侧重于微管电极作为 GDE 的气体电解。用于气体电催化的 GDE 具有重要意义，因为它们通过向反应位点连续输送反应物进料来有效地提高反应速率，解决了传质阻力问题，而微管 GDE 可以解决平面 GDE 的几个问题。在最后一节中，