E-mail: printing technologies and continuous flow microreaction systems are rapidly gaining attention in the domain of heterogeneous catalysis. E-mail: b Industrial Decarbonisation Research and Innovation Centre (IDRIC), Heriot-Watt University, Edinburgh EH14 4AS, UK c Nano & Micro Additive Manufacturing of Polymers and Composite Materials Laboratory “3D LAB”, Advanced Functional Materials & Nanotechnology Group, Centro de Investigación en Materiales Avanzados S. * ab a Research Centre for Carbon Solutions (RCCS), School of Engineering & Physical Sciences, Institute of Mechanical, Process & Energy Engineering, Heriot-Watt University, Edinburgh EH14 4AS, UK. A, 2023, 11, 5408-5426 3D direct ink printed materials for chemical conversion and environmental remediation applications: a review