It can be a synergistic role. A generalized answer would be to tackle "sub-optimal bonding chemistry" in catalytic systems. However, this does not completely satisfy the context as it is dependent on what expectations the scientist has in view especially when dealing with either low or high concentration samples of nanoparticles.

Surface modifications have a guiding role in advancing catalytic activity of nanoparticle catalysts by adjusting surface properties such as electronic structure, availability of active sites, and adsorption attributes. The governing role of surface modifications is rooted in their control of the surface chemistry, which, in turn, directly affects selectivity, reaction rates, and sustainability as most catalytic reactions occur on the surface. One of the primary functions of surface modifications is adjusting the nanoparticles' electronic features, which one can achieve through the introduction of heteroatoms or functional clusters or the formation of core-shells. Such modifications cause changes in the handing out and denseness of electronic charge at the surface, thus altering how the reactants, intermediates, and products' adsorption energies. Using non-metal elements to dope the metallic nanoparticles like nitrogen or sulfur would be one such way to optimize binding strength to certain species by adjusting the d-band center (Li et al., 2018). Another approach is employing core-shell nanoparticles, which involve coating another element's core with one metal thin shell, thus creating electronic effects that improve catalytic functionality (Zhang, Xia, & Liu, 2019).

Furthermore, alterations in the surface increase the number and availability of the active sites. Surface etching, ligand exchange, or defect formation techniques improve the surface roughness and porosity, exposing more reaction sites. For example, a high catalytic activity can be achieved when nanoparticles are etched selectively in order to increase catalytic turnover by removing the covering ligands blocking the surface or etching specifically the nanoparticles (Chen et al., 2017). According to previous studies, engineering defects through creating vacancies or edge steps has provided high catalytic activity, mainly in metal oxides and sulfides (Sun et al., 2020). Moreover, surface modifications are crucial to preventing sintering and aggregation under reaction circumstances, thereby boosting catalyst stability. It is possible to enhance nanoparticles' stability by using functional ligands on the nanoparticle surface or by attaching them to supports to enhance their dispersion properties and increase resistance to deactivation (Chen et al., 2017).

As a result, an increased surface area thus preserves the high catalytic performance throughout the extended application period. Besides improving the availability of active sites, surface modification also changes the nanoparticles' electronic properties. Having control over the electronic properties of the nanoparticles gives researchers more control over the adsorption of reactants, products, and intermediates. This is partly why core-shell nanoparticles and functional coatings are so effective, as they can be precisely engineered to create electronic environments that are favorable to the catalytic reactions of interest. By improving catalytic performance in this way, even very complex reactions can be optimized to produce the desired results (Li et al., 2018). For example, the creation of a catalytic environment that is more electron-rich will help reactants to bind more easily and intermediates to form more readily, thus enhancing the overall reaction kinetics and selectivity (Zhang, Xia, & Liu, 2019). In addition to this, the ratio of active metal atoms to the oxygen atoms on the surface is critical. This ratio influences the oxygen binding capability, which, in turn, dramatically affects the possible catalytic mechanisms as metal atoms are the main adsorption and activation sites (Sun et al., 2020).

Similarly, the structural alterations can lower energy activation for various important reaction steps or raise the desorption energy of some critical intermediates. These adjustments improve the catalyst's ability to break or to form chemical bonds at the interface of the solid/liquid or solid/air processes (Chen et al., 2017). As a result, such changes can influence everything from the catalytic activity to the possible surface degradation and poisoning (Zhou et al., 2016). In conclusion, adjusting surface properties such as electronic configurations, active site numbers, and resistance to environmental conditions in the catalytic process has resulted in surface modifications of nanoparticles. An increase in selectivity, reaction rate, and efficiency of the catalytic process is facilitated by surface modifications to nanoparticles. Such tailored surface properties contribute significantly to improving catalytic performance for several different chemical conversions.

References:

Chen, Y., Duan, J., Jaroniec, M., & Qiao, S. Z. (2017). Heterostructured photocatalysts. Chemical Society Reviews, 46(7), 1867-1885.

Li, X., Zhang, J., Hou, Y., & Chen, Y. (2018). Nitrogen-doped carbon materials for metal-free catalytic reactions. Chemical Communications, 54(47), 5994-6015.

Liang, Y., Li, Y., Wang, H., Zhou, J., Wang, J., Regier, T., & Dai, H. (2019). Co₃O₄ nanocrystals on graphene as a synergistic catalyst for oxygen reduction reaction. Nature Materials, 10(10), 780-786.

Sun, Y., Cheng, H., & Tang, Z. (2020). Defect engineering in metal oxide catalysts for enhanced catalytic performance. Advanced Materials, 32(23), 1907848.

Zhang, H., Xia, B. Y., & Liu, Z. (2019). Engineering the surface chemistry of nanomaterials for enhanced catalysis. Chemical Reviews, 119(15), 9397-9450.

Zhou, W., Gao, X., Liu, D., & Chen, X. (2016). Surface ligand engineering of colloidal nanocrystals for catalytic applications. Chemical Society Reviews, 45(23), 6420-6433.