Design and construction of a simple UHV‐compatible high‐pressure reaction cell

The design of a high pressure reaction cell, internal to a commercial ultrahigh vacuum (UHV) system that provides for high-pressure catalytic reaction studies with UHV surface science capabilities, is described in detail. This reaction cell is comprised of the following two elements: (a) a sample-holding flange that extends from the central manipulator and (b) a self-contained sealing "cup" that is attached to an existing 6-in. flange. This reaction cell operates hydraulically and features a small cell volume (approximately 45 ml) that can be pressurized up to 5 atm, sample heating and cooling capabilities, continuous gas flow or static batch modes, relatively rapid sample transfer (1-2 min) between high- and low-pressure conditions, and gas product analysis. The principle advantage of the present design over the previous ones is its compatibility with commercial UHV systems, without the requirement of bell jar reinforcement. Results of methane activation studies on a Pd(679) single crystal that exemplify the bridging of the pressure gap using this reaction cell are also briefly presented.