The Mechanism and Rate-Determining Step of Catalytic Ammonia Oxidation on Pd(332) at High Temperatures

IF 11.3 1区化学 Q1 CHEMISTRY, PHYSICAL

ACS Catalysis Pub Date : 2025-06-05 DOI:10.1021/acscatal.5c01448

Jan Fingerhut, Jessalyn A. DeVine, Rongrong Yin, Mark E. Bernard, Alice Bremer, Dmitriy Borodin, Kai Golibrzuch, Theofanis N. Kitsopoulos, Daniel J. Auerbach, Hua Guo, Alec M. Wodtke

{"title":"The Mechanism and Rate-Determining Step of Catalytic Ammonia Oxidation on Pd(332) at High Temperatures","authors":"Jan Fingerhut, Jessalyn A. DeVine, Rongrong Yin, Mark E. Bernard, Alice Bremer, Dmitriy Borodin, Kai Golibrzuch, Theofanis N. Kitsopoulos, Daniel J. Auerbach, Hua Guo, Alec M. Wodtke","doi":"10.1021/acscatal.5c01448","DOIUrl":null,"url":null,"abstract":"Despite its immense practical importance in industrial production of nitric acid, the mechanisms of catalytic ammonia oxidation on platinum group metals remain controversial. In this work, we employ velocity-resolved kinetics to study ammonia oxidation on a model Pd(332) catalyst between 600 and 700 K. We obtain the temporal evolution of gas-phase reactants (NH3), products (NO, H2O) and─with the help of femtosecond laser-induced desorption─of a reaction intermediate, N*. The reaction exhibits the prompt appearance of H2O and the delayed formation of NO; the rate-determining step is the reaction N* + O* → N*O occurring at step sites. This means that N* is the longest-lived reaction intermediate, an insight that helps explain formation of byproducts like N2 and N2O. We present a mechanism that explains all experimental observations, based on transition-state theory calculations and using input from density functional theory. We also show that N*O desorption is accelerated by coadsorbed oxygen.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"52 1","pages":""},"PeriodicalIF":11.3000,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.5c01448","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}

引用次数: 0

Abstract

Despite its immense practical importance in industrial production of nitric acid, the mechanisms of catalytic ammonia oxidation on platinum group metals remain controversial. In this work, we employ velocity-resolved kinetics to study ammonia oxidation on a model Pd(332) catalyst between 600 and 700 K. We obtain the temporal evolution of gas-phase reactants (NH₃), products (NO, H₂O) and─with the help of femtosecond laser-induced desorption─of a reaction intermediate, N*. The reaction exhibits the prompt appearance of H₂O and the delayed formation of NO; the rate-determining step is the reaction N* + O* → N*O occurring at step sites. This means that N* is the longest-lived reaction intermediate, an insight that helps explain formation of byproducts like N₂ and N₂O. We present a mechanism that explains all experimental observations, based on transition-state theory calculations and using input from density functional theory. We also show that N*O desorption is accelerated by coadsorbed oxygen.

Abstract Image

查看原文本刊更多论文

高温下Pd（332）催化氨氧化机理及速率决定步骤

尽管铂族金属催化氨氧化在硝酸工业生产中具有巨大的实际意义，但其机理仍存在争议。在这项工作中，我们采用速度分辨动力学研究了模型Pd（332）催化剂在600和700 K之间的氨氧化。我们得到了气相反应物（NH3）、生成物（NO, H2O）和反应中间体N*（借助飞秒激光诱导解吸）的时间演化。反应表现为H2O的快速生成和NO的延迟生成；速率决定步骤是N* + O*→N*O发生在步位。这意味着N*是寿命最长的反应中间体，这有助于解释N2和N2O等副产物的形成。我们提出了一种解释所有实验观察的机制，基于过渡态理论计算和使用密度泛函理论的输入。我们还发现共吸附的氧加速了N*O的脱附。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

ACS Catalysis CHEMISTRY, PHYSICAL-

CiteScore

20.80

自引率

6.20%

发文量

1253

审稿时长

1.5 months

期刊介绍： ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels. The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.