In the race to shape the future of petrochemical production, optimising catalytic processes has become a key focus for the industry. Ever-intensifying demand for cleaner fuels and stricter environmental regulations mean that unprecedented process efficiencies are needed to stay competitive. These innovations are being driven by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), an essential analytical technique that decodes catalytic processes through real-time insights into their behaviour under operational conditions, where it matters most.
Traditional catalyst analysis captures only static snapshots and misses the true dynamic nature of chemical reactions. In contrast, DRIFTS enables petrochemical professionals to track transient intermediates and other short-lived species in real time. This approach is helping reshape how heterogeneous catalysts are designed, tested and optimised to solve future challenges.
What is DRIFTS?
DRIFTS is a type of reflectance IR spectroscopy used to analyse powders and rough solids based on internal radiation scattering. Incident infrared light can either undergo a single (specular) reflection at the surface, or multiple internal reflections within the particulate solid, producing diffusely scattered light where the reflected angle is not equal to the incidence angle (see Figure 1). In DRIFTS, the diffuse component is specifically collected and analysed.1
Mathematically, diffuse reflectance is described using plane-parallel layer models and measurements are often transformed2 according to the Kubelka–Munk equation:
Here, K is the molar absorption coefficient, s is the scattering coefficient and R∞ is the reflectance when the sample is thick enough to prevent radiation transmission. The amount of diffusive scattering is highly influenced by sample characteristics including refractive index, particle size, packing density and homogeneity. Thus, to ensure high-quality and reproducible DRIFTS spectra for quantitative analysis, researchers must pay attention to the following:
- Particle size: Ensure uniform size ≤50 µm for narrower bandwidths and accurate intensities.
- Dilution: Mix the sample ~5% w/w with a non-absorbing matrix (e.g., KBr) to enhance diffuse reflections.
- Homogeneity: Ensure thorough mixing of the sample.
- Packing: Loosely pack the sample to maximise beam penetration.
It’s worth noting that DRIFTS spectra differ from traditional transmission IR spectra, particularly in terms of band intensity. Typically, low-intensity bands appear more pronounced relative to intense bands, while strong bands exhibit broader, rounder peaks.3 Many FT-IR software packages offer a Kubelka–Munk conversion to account for some of these differences.
Dynamic catalyst insights with DRIFTS
The strength of DRIFTS lies in its ability to provide detailed, actionable data that can be used to fine-tune catalyst performance. Some of the key benefits include:
Real-time monitoring
Industrial chemical processes often involve multiple intermediates and surface species interacting over a catalyst. As DRIFTS permits in situ analysis, these interactions can be observed in real time. For example, it can detect the formation and decay of critical but transient intermediates in catalytic cracking or reforming processes. With a better understanding of reaction mechanisms, engineers can improve overall efficiency.4
Surface sensitivity
DRIFTS offers unparalleled sensitivity to surface-bound species, which are often the key drivers of catalytic activity. It aids optimisation of catalyst surfaces to enhance performance by identifying how these species interact with reactants and evolve during a reaction. This is particularly valuable in applications such as hydroprocessing, where surface interactions govern the removal of impurities like sulphur and nitrogen.5
Non-destructive analysis
A significant advantage of DRIFTS is its non-invasive nature. Catalysts can, in principle, be analysed in their operational state without disrupting the system. This is especially valuable during process development, allowing for consistent and repeatable testing, and makes DRIFTS a preferred choice for industrial labs seeking to maximise productivity.6
Expanding applications in the petrochemical industry
DRIFTS has proven transformative in several critical applications, providing insights that are redefining the way catalysts are used and designed.
Catalytic cracking
Cracking is a cornerstone of the petrochemical industry, converting heavy hydrocarbons into lighter, more valuable products such as petrol and diesel. Crucially, DRIFTS allows engineers to track the formation and consumption of reaction intermediates in these mechanistically complex processes. The technique can reveal how certain molecular fragments interact with the catalyst surface, enabling fine-tuning of conditions for maximal yield and selectivity.7 Researchers have also applied DRIFTS to understand boron-based nickel passivation in cracking catalysts, overcoming difficulties encountered with other analytical techniques.8
Hydrotreating
The demand for low-sulphur fuels, driven by stricter environmental regulations such as the Euro VI and EPA Tier 3 standards, has made hydrotreating an essential process in modern refineries. By providing real-time data on the removal of sulphur and nitrogen compounds, DRIFTS also helps optimise this process as it reveals how these impurities interact with the catalyst surface. Engineers can then develop improved catalyst formulations to produce cleaner fuels while minimising energy consumption.7
Reforming
Reforming processes are vital for the production of high-octane components used in petrol. DRIFTS gives detailed information about the behaviour of catalysts during conversion of feedstocks like naphtha, allowing for more efficient catalysts to be designed with prolonged operational lifespan at high temperatures, in turn reducing downtime and improving profitability.7
Catalyst development and testing
Beyond these specific applications, DRIFTS has become an indispensable general tool in catalyst development. Through real-time analysis of catalyst performance under varying conditions, the technology accelerates iterative design, testing and optimisation of new catalysts. This is particularly valuable in emerging areas like biofuel production and CO2 utilisation, where new processes are essential to meet sustainability goals.
Enabling sustainability and efficiency
In the drive towards net zero, the petrochemical industry is under increasing pressure to reduce its environmental footprint without compromising efficiency. DRIFTS is uniquely positioned to help the sector meet these dual objectives.
Enhancing energy efficiency
Catalysts designed using insights from DRIFTS often operate under milder conditions with lower energy requirements. This not only saves on operational costs; it also lowers the carbon footprint of industrial processes.7
Minimising waste
The ability to optimise catalysts for specific reactions enhances their selectivity, resulting in higher chemical yields and fewer by-products. This reduces waste and contributes to overall process sustainability.7
Extending catalyst lifespan
Catalysts are a significant investment, and their longevity is crucial for cost control. Reaction monitoring using DRIFTS can elucidate catalyst deactivation mechanisms and identify conditions that prolong their operational life, resulting in less frequent catalyst replacement and bringing both economic and environmental benefits.7
DRIFTS beyond petrochemicals
The potential applications of DRIFTS extend far beyond the petrochemical industry. For instance, in the pharma sector it aids quality control of active pharmaceutical ingredients (APIs) and development of drug formulations for enhanced efficacy. In environmental science, DRIFTS is applied to monitor soil contamination and analyse surface interactions of pollutants, thereby supporting remediation efforts. The food industry uses DRIFTS to analyse ingredients, detect contaminants and study surface properties in powdered and granular materials. Meanwhile, DRIFTS is pivotal in understanding surface chemistry during the development of advanced materials, such as coatings, composites and catalysts for renewable energy applications.
In sum, its versatility, non-destructive capabilities and capacity for real-time analysis make DRIFTS a truly indispensable tool across diverse sectors, driving innovation and precision in countless applications.
Challenges of adoption and future directions
While DRIFTS has immense potential, its adoption in the petrochemical industry is not without challenges. In particular, the need for specialised equipment and expertise can limit its accessibility, particularly for smaller operations, although ongoing advancements in instrumentation and training are helping to overcome these barriers.
Looking ahead, continued integration of DRIFTS with other analytical techniques promises to unlock even deeper insights. For example, one study combined real-time DRIFTS with mass spectrometry to investigate potassium hydroxide-coated catalysts for methanol steam reforming, finding differences in surface-bound species that explained their enhanced performance.9 Another exciting frontier is the use of machine learning to analyse DRIFTS data, which may enable further efficiency improvements through rapid identification of patterns and trends that would be difficult to discern manually.
The future of petrochemical innovation
As you now know, DRIFTS is more than just a tool for analysis – it’s a catalyst for innovation. The detailed, dynamic view of catalytic processes that it provides can empower petrochemical professionals to optimise operations, reduce costs and keep pace with changing environmental standards.
For an industry grappling with the challenges of efficiency, sustainability and compliance, DRIFTS represents a linchpin of future possibility. Its impact on the petrochemical sector will only grow as it continues to evolve, driving advancements that benefit both the bottom line and the planet.
If you’re ready to revolutionise your catalytic processes, there’s no better time to explore the potential of DRIFTS technology. Why not start today?
Related resources
Infographic: Catalysts for change – driving efficiency in petrochemicals – Specac Ltd
Developing catalysts to drive innovation – Specac Ltd
Catalytic studies using FTIR reaction cells – Specac Ltd
Fundamental catalyst research is key to advancing the global transition from fossil fuels – Specac Ltd
References
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2. F. C. Meunier, React. Chem. Eng., 2016, 1, 134–141.
3. P. Larkin, Infrared and Raman Spectroscopy, Elsevier, Waltham, MA, 2011.
4. DRIFTS: Diffuse reflectance infrared Fourier transform spectroscopy, https://www.swri.org/sites/default/files/brochures/drifts.pdf, (accessed January 2025).
5. C. Rodriguez, S. Moreno and R. Molina, MethodsX, 2023, 10, 102169.
6. J. Workman, Jr, Advances in Infrared Spectroscopy for Today’s Spectroscopists, 2024, 39, 22–28.
7. M. S. Akhtar, S. Ali and W. Zaman, Catalysts, 2024, 14, 841.
8. C. C. Zhang, J. Shi, S. Hartlaub, J. P. Palamara, I. Petrovic and B. Yilmaz, Catal. Commun., 2021, 150, 106273.
9. A. Kaftan, M. Kusche, M. Laurin, P. Wasserscheid and J. Libuda, Appl. Catal. B-Environ., 2017, 201, 169–181.