Comment

Photocatalytic hydrogen peroxide formation is an advancing field with various approaches motivated by the promise of a green oxidant and energy carrier for a sustainable future. An assessment on quantification methods, sacrificial agents and best practices is provided to avoid false positives and support progress in the field.

Data science and machine learning have the potential to accelerate the discovery of effective catalysts; however, these approaches are currently held back by the issue of negative results. This Comment highlights the value of negative data by assessing the bottlenecks in data-driven catalysis research and presents a vision for a way forwards.

The discovery of robust and efficient water oxidation catalysts based on first-row transition metal complexes is still a challenge. Here, we describe the underlying chemistry related to the deactivation pathways of first-row transition metal complexes and put forward a series of principles and basic checks to enable the development of robust catalysts.

Metrics are a useful way to assess biocatalyst performance and, when compared to techno-economic targets, can help set goals for further enzyme and bioprocess research and development. Here, we outline some of the remaining challenges to ensure wider acceptance of this approach, both in industry and in academia.

Electrocatalytic conversion of CO₂ into useful products can contribute to the Paris goals on the basis of abundant low-carbon power and technological advances. From R&D to policy, areas are highlighted in which coordinated efforts can support commercialization of such capture and catalytic technologies while deploying the required infrastructure.

Identifying the active sites in supported catalysts comprising isolated metal atoms and subnanometric clusters is challenging because of the difficulty in obtaining detailed structural information under reaction conditions. Here, we discuss the limitations and pitfalls that may be encountered and provide suggestions accordingly.

This Comment articulates simple metrics that can guide early catalysis research to make the manufacture of fuels and chemicals sustainable and affordable. These metrics cover resource efficiency (waste/CO₂ production, selectivity) as well as conversion performances that look at different aspects of the process.

The Fischer–Tropsch product, water, is regularly hypothesized to be the driving force for catalyst deactivation. Cobalt nanoparticles may be oxidized to CoO, form mixed-metal oxides with supports, or sinter to larger particles. This Comment discusses the feasibility of these deactivation pathways, highlighting the importance of in situ characterization.

Considerable research achievements were made to address the plastic crisis using biotechnology, but this is still limited to polyesters. This Comment aims to clarify important aspects related to myths and realities about plastic biodegradation and suggests distinct strategies for a bio-based circular plastic economy in the future.

Two different types of H₂O₂ selectivity are reported for the electrochemical synthesis of H₂O₂: molar fraction selectivity and Faradaic selectivity. Here we revisit their definitions and discuss the best way to report H₂O₂ selectivity, which can help to avoid misunderstandings or unfair performance comparisons in this growing field.

Humankind faces many challenges to continue social and technological development in a sustainable manner. This Comment elaborates how increasing the synthetic capacity of biocatalytic systems can contribute to the United Nations Sustainable Development Goals.

Catalysis is essential in the automotive and transportation sectors to target the United Nations sustainable development goals for climate change and the environment. To comply with both the ambitious United Nations goals and step-by-step stringent emission regulations, innovative and economically viable catalytic systems will be a key element in meeting these challenges.

The global energy and transportation landscapes are changing rapidly, and that brings with it evolving opportunities and catalyst research needs for hydrogen and fuel cells.

For the foreseeable future, we will continue to rely on the internal combustion engine for mobility of people and goods. The ubiquitous three-way catalyst does not work below 350 °C, with appreciable O₂, nor does it control soot. Low temperature catalysis, chemical trapping and filtration will grow in need, and represent research opportunities.

PGM-free catalysts for oxygen reduction represent a long-term, high-risk research and development approach with high potential impact on the single greatest cost contributor to automotive fuel cell stacks.

Radical intermediates are key species in many chemical transformations. Recent advances have provided a new suite of selective radical alkylation reactions. This Comment highlights pioneering studies using alkyl amines that act as radical precursors in a number of catalytic processes by their conversion to alkylpyridinium salts.

The preeminent Haber–Bosch process has been feeding humankind for more than one hundred years. Are electrochemical pathways for ammonia synthesis able to compete with it in the future? Electrocatalysts, electrolytes and novel cell design may be key.

Establishing an efficient catalytic system for direct amidation reactions has remained a formidable challenge for years. This Comment will focus on potential new directions in the hope of moving this field forward.

Developing catalytic reactions for organic synthesis is the central goal of countless research groups worldwide. High-throughput experimentation is invaluable for this pursuit, with the requisite tools becoming increasingly available to both industrial and academic research labs.

Databases of computational results hold high promise for accelerating catalysis research. Still, many challenges remain and consensus on facets such as metadata, reliability and curation is crucial to transform the hype into an attractive technology.